Ben: a 51% attack has always been an acknowledged way to cheat the system; and the computing power…
Dr. Drew Miller

It is legitimate.

However as long as one honest node remains, the chain is sovereign and can be rebuilt.

You cut it down, someone had it saved on a hdd not on the network. It can be rebuilt. (many people run backups)

The decentralised trust remains. You can’t really kill it without a worldwide emp or something.

This is why its cool, and why you don’t centralise nodes ;)

Read my article if you want to know more.