Just as another thought experiment would be how much would it cost to get enough ETH while people are selling theirs to do this to launch your own 51% attack on ETH.

The fact that there is no real work involved just having enough money to buy enough of a specific coin has always been a weakness of all POS coins.
And now that there are ETH ETFs there is an incentive for people to be able to short the ETFs if they think their value will go down.

Think about it, get enough funds to buy the companies I discussed above that host a bunch of the ETH staking nodes, while simultaneously buying ETH and spinning up your own nodes and then a simple 51% attack against ETH.

-Dave