Picture this scenario: Core and Knots chose not to relay large op_returns. Meanwhile, the biggest KYC miners controlling around 90% of hash rate and don't gf about reputation put up an API for pricing and direct submission of transactions - fast and centralized. They mine the transactions into blocks and send them out to core and knots. Core and knots, not seeing a complete mempool, now have broken pricing, and wallets start connecting to the miners' API for better UX, because they're fast (centralized) and have more accurate market pricing of sats/vb.