A point of pedantry, the chain was not rolled back. Funds were simply reassigned from one address to another in a hard fork. (It's not an important distinction functionally, but Buterin et al were able to use this point to refute criticism in the past).

On your actual point though - Ethereum got big enough that full on hard forks like that to reassign funds became pretty much infeasible for "normal" hacks, *but* it could just be that it depends whose funds are at risk. Also, because it's now proof of stake it could easily be the case that if the amount stolen is more like 25% + of the supply, they would go back to the "fund reassignment" approach. This is one of the several offshoot weaknesses of proof of stake.