MEV Aggregator Drift (Collusion Packs): Structural Centralization of Extractive Power in PoS and DeFi Systems

Maximal Extractable Value (MEV) has evolved from a theoretical artifact of transparent transaction ordering into a dominant economic force shaping Proof-of-Stake (PoS) blockchain ecosystems. While early research framed MEV as an unavoidable but competitive phenomenon, recent infrastructure developments—particularly MEV relays, aggregators, and proposer-builder separation (PBS)—have enabled the consolidation of extractive power into coordinated intermediary groups. This paper introduces MEV Aggregator Drift, a structural phenomenon in which MEV extraction progressively centralizes into opaque, off-chain coordination clusters (“collusion packs”) that undermine validator neutrality, distort protocol incentives, and introduce cartel-like dynamics without explicit on-chain collusion. We analyze the economic drivers, execution mechanisms, and systemic risks of MEV collusion across PoS and DeFi systems, and argue that existing mitigations focus on efficiency while neglecting enforceable neutrality. Finally, we outline mitigation requirements centered on validator accountability, behavioral monitoring, and transaction ordering attestation.