>The catch is that people will notice 51% attacks.

The thing about crypto is that the majority hashrate/stake gets to decide what is an "attack" and what isn't. This behavior isn't a bug, it's a feature and it's what separates crypto from fiat.

With PoW, sooner or later the attacker will run out of money. When they stop paying for the hashrate, their votes all goes away, they don't get extra points for being the top miner at one point in time. With PoS, getting a majority means that your majority will actually increase over time unless someone actively decides to burn the cash necessary to stop you. The longer the community waits/debate over it, the harder it will be to remove the "attacker".

Right, the majority decides what is an "attack" in that it decides which chain to use, and the longest chain wins. But that's not the issue. People (or automated systems) can decide on their own what is an attack. They see transactions being reversed after several confirmations and say "the blockchain is compromised, so I won't use it anymore."

Yes with PoS it's harder to remove the attacker. But the attacker also stands to lose far more money than the attack can possibly be worth.