I see so I was mistaken about that. I still don’t understand why people don’t see that it would be trivial for a major bank (or now that Bitcoin has grown, a government) to look into making enough computational power they would destroy it.
So yes, 51% control could be usurped by a dedicated attacker - but the resources are no longer trivial. And as noted, this "control" doesn't buy you a great deal unless you keep it going for eternity, and for the time period you do have control all you can do is basically stop it working properly by preventing new transactions - rewriting history is exponentially more expensive the farther back you try to go.
If this were a big transaction, I might choose to wait for more than one confirmation before completing my end of the transaction. The longer I wait, the more expensive it becomes for you to conduct your 51% attack.
It really is prohibitively expensive, to conduct such an attack, when you consider a few other factors. I could double spend the money to myself, but after news of such an attack came out, the price likely could crash, reducing the prize.
Not to mention opportunity cost. If you have the means to conduct a 51% attack it means you have a lot of capital and expertise. You could put those two together to make a giant pile of money through legitimate means, like operating a hedge fund. The risk is a lot less.
The only group that would be motivated enough and capable enough to perpetrate such an attack would be a state, and why would they bother when, like was mentioned elsewhere, they could attack bitcoin with the stroke of a pen, via regulation etc. It's waaay less effort.
Also, would like to note that Bitcoin can also function as store of value just like Gold.
Any news about Lightning? Is that running live now?
For sure these banks wouldn't use their own hardware, but hire a new team, new hardware etc.