Why Is Bitcoin Simple but Ethereum So Complex? The Structural Case for FOCIL
3-Point Summary
- Bitcoin’s simple block production model naturally avoids censorship, incentive conflicts, and MEV-driven unpredictability.
- Ethereum’s multi-stage, MEV-driven pipeline creates structural risks that require protocol-level guarantees like FOCIL.
- FOCIL and the Hegotá upgrade mark a turning point toward restoring predictable inclusion and enabling Ethereum’s evolution into a global settlement layer.
Ethereum’s complex MEV-driven pipeline requires FOCIL to restore predictable inclusion and reintroduce Bitcoin-style stability.
20‑Second Shorts Video (Updated August 22, 2026)
Bitcoin Is Simple… So Why Did Ethereum Get So Complicated? (FOCIL Explained) #Ethereum #FOCIL #BitcoinVsEthereum #BlockchainInsights
Why Ethereum Needs FOCIL: The Structural Dilemma Born from Bitcoin’s Simplicity and Ethereum’s Complexity
Bitcoin and Ethereum are both public blockchains, but the way they produce blocks and include transactions is fundamentally different. Bitcoin’s simple structure means it faces almost no issues around censorship risk, incentive conflicts, or unpredictability in transaction inclusion. Ethereum, by contrast, has a complex structure driven by smart contracts and the economic gains that come from reordering transactions inside a block. FOCIL (Fork-Choice Inclusion List), scheduled for introduction in the Hegotá upgrade around 2027, is the core mechanism Ethereum has chosen to address these structural problems.
Today, Ethereum’s mainnet still relies on an external PBS (Proposer‑Builder Separation) system through MEV‑Boost rather than a fully enshrined, protocol-level PBS. The first version of enshrined PBS will only appear in the Platåberget testnet fork on August 20, with mainnet integration planned for the second half of 2026. This continued dependence on external builders—and the complexity introduced by transaction ordering incentives—is precisely why Ethereum requires mechanisms like FOCIL to guarantee inclusion, reduce builder dominance, and restore predictability in block construction.
The direction in which Ethereum is evolving to solve these structural issues has already been explored in previous articles. In particular, Ethereum’s goals of strengthening censorship resistance, mitigating builder centralization, and increasing MEV transparency in the Beacon Chain–Proposer–Builder relationship are covered in Bitcoin‑Style Competition Among Ethereum Builders: A Complete Guide to the ePBS Architecture. Ethereum’s innovations aimed at achieving five key objectives—reducing builder centralization, decentralizing block contents, strengthening censorship resistance, laying the groundwork for shorter slot times, and reducing node operation complexity—are explained in How Focil and ePBS Are Rewriting Ethereum’s Block Production Pipeline and Ethereum’s Block Reborn: Why FOCIL and ePBS Completely Redesign the Slot Structure. This article continues that line of analysis, focusing on why Ethereum’s complex block production pipeline—so different from Bitcoin’s simplicity—ultimately requires FOCIL.
1) Bitcoin vs Ethereum: Structural Differences in Block Production
Bitcoin: A Simple Block Production Flow
Bitcoin’s block production process is highly intuitive. Miners construct blocks directly, include transactions, and then propagate those blocks to the network. Because there are no smart contracts and no intermediate roles, MEV does not arise in any meaningful way, and the transaction inclusion process remains simple. This simplicity translates into predictability, strong censorship resistance, and stable incentive alignment.
- Miner solves a hash puzzle to gain the right to produce a block
- Higher-fee transactions are prioritized for inclusion
- Block is propagated across the network
- Nodes verify the block and append it to the chain
Ethereum: A Multi‑Stage, MEV‑Driven Block Production Pipeline
Ethereum runs a smart contract–based ecosystem with many applications, and large economic gains (MEV) can arise depending on transaction ordering. As a result, block production is split across multiple roles—builders, relays, and proposers—forming a more complex pipeline. This structure increases efficiency and MEV revenue, but it also introduces structural risks around censorship, incentive conflicts, and unpredictability in transaction inclusion.
- Builder: Assembles blocks to maximize MEV
- Relay: Verifies and forwards builder‑produced blocks
- Proposer: Selects the final block to be included on chain
2) The Problem of Transactions Being Censored or Excluded
Bitcoin
In Bitcoin, the single‑miner structure leaves almost no economic or technical incentive to deliberately exclude specific transactions. Because MEV does not exist in practice, there is no additional profit to be gained by omitting particular transactions.
Ethereum
In Ethereum, builders can exclude certain transactions to maximize MEV, and relays can choose to block specific addresses based on policy. There have been real cases where some relays excluded addresses following OFAC sanctions.
- Builders can exclude transactions to maximize MEV
- Relays can block specific addresses as a matter of policy
How FOCIL Addresses This
FOCIL designates “must‑include transactions” at the chain level, structurally limiting censorship. Even if builders or relays attempt to exclude them, proposers can forcibly include those transactions based on the FOCIL list.
- Inclusion obligations are enforced at the chain level
- Proposers can include transactions even if builders or relays exclude them
3) Incentive Conflicts Among MEV, Builders, and Proposers
Bitcoin
Bitcoin has no smart contracts and almost no MEV, so the block production process does not involve complex overlapping interests. Miners simply aim to maximize block rewards and fees, and transaction ordering does not create a separate economic game.
Ethereum
In Ethereum, builders prioritize MEV maximization, proposers prioritize censorship resistance and network trust, and relays may prioritize their own policy filters. Because these goals do not always align, structural tension arises around which transactions are included and in what order.
- Builder: MEV maximization
- Proposer: Maintaining network reliability and censorship resistance
- Relay: Applying its own policy filters
How FOCIL Addresses This
FOCIL ensures that transactions designated by the proposer as “must‑include” are actually included in the proposed block. This reduces incentive conflicts within the MEV‑driven structure. Even if a builder omits such transactions, the proposer can still include them based on the FOCIL list.
- Proposers are given a minimum inclusion obligation
- The MEV‑centric structure is prevented from undermining network trust
4) Unpredictability in Transaction Inclusion
Bitcoin
In Bitcoin, transaction inclusion is largely fee‑driven, making it highly predictable. Because there are no intermediate stages, the risk of delays or arbitrary exclusion is low.
Ethereum
In Ethereum, MEV, PBS architecture, and relay policies interact to make transaction inclusion timing uncertain. Even with high gas fees, transactions can be pushed back or delayed.
How FOCIL Addresses This
FOCIL provides a minimum level of predictability by guaranteeing that certain transactions will be included in upcoming blocks. This improves user experience and makes it easier for institutions and enterprises to adopt Ethereum as a settlement layer.
- Provides a minimum guarantee on inclusion timing
- Strengthens Ethereum’s reliability as a settlement layer
Conclusion: FOCIL Reintroduces Bitcoin‑Style Stability on Top of Ethereum’s Complex Structure
Bitcoin’s simple structure naturally provides censorship resistance, predictability, and stable incentives. Ethereum, however, has faced structural issues due to the complexity introduced by smart contracts and the MEV ecosystem. FOCIL is an upgrade designed to reintroduce the kind of stability Bitcoin enjoys, but in a way that fits Ethereum’s more complex architecture. Hegotá will be a pivotal moment in Ethereum’s evolution toward becoming a global settlement layer.
Younchan Jung
Researcher exploring structural shifts in AI, blockchain, and the on‑chain economy.
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