Only exchanges will have the resources necessary to validate blocks on all shards. It's really fucked for the average user. My prediction is that Ethereum will be an exchange-dominated chain somewhat soon after the merge (which is the rugpull switch from PoW to PoS). Exchanges, especially those with their own token, like Binance, could offer higher yield to ETH holders in order to get them to stake with them instead of DAOs, giving them further power to do MEV, making decentralized exchanges unusable, which pushes people to centralized exchanges, giving them more fees.