I think this assumes big holders care enough, and big holders are ETFs, corporations, whales, and soon maybe even nation states themselves, and I don't think they would care enough if a 51% attack didn't even affect them.

For example, I have to admit that even in a 51% attack, I probably wouldn't sell my bitcoins. It's still better than fiat. At least someone would have to maintain 51% to censor transactions. Also, it would mean I would have to travel far to get them out of cold storage.

Will you go back to fiat just because a few morally questionable people were censored?