this is not how markes work. while trying to buy 2/3 by of a semi-stable (in that time frame) amount of ETH, you will skyrocket the price and have to pay more f

this is not how markes work. while trying to buy 2/3 by of a semi-stable (in that time frame) amount of ETH, you will skyrocket the price and have to pay more for each additional ETH. A huge amount of ETH is already staked aka out of the system since you can not unstake them at the moment. You can not liquidate your staked ETH regardless how much money you throw around. This is not a practical attack vector you would literaly >100x the ETH price. This aspect also differs from the PoW approach where you take a source from outside of the system (Hardware) to participate. And since there is a 'infinite' number of Hardware/Hashpower you could accumulate over time attacks are easier (still hard for different reasons) to perform. But lets assume you archive to controll 2/3rds of validators, you can not start staking the very next second. There is a queue (I think of some days) and people will recognize the attack before you will be able to perform it and people will simply blacklist you for their own sake.