It is much cheaper to run a staking operation but not 0-cost. You still need an internet connection to pay and a bit of energy to run your validator. You may ow

It is much cheaper to run a staking operation but not 0-cost. You still need an internet connection to pay and a bit of energy to run your validator. You may owe taxes on staking rewards, etc... So there is likely to be some selling by validators. Rewards are also much lower, issuance of ETH is cut by 90%, for example. Also you lock-up capital which has an opportunity cost and must competes with every other investable asset. As the barriers to entry staking are negligible (just acquiring a liquid staking derivative like rETH, for example) it means that everyone willing to stake will likely do so which drops the returns lower, which may push some stakers out as they see better investing opportunities. So staking is likely going to have thin margins in the future and will give a rate of return that is fairly priced given its risk adjusted returns.