That hasn't been true for years.
Back in 2016 a then-huge Ethereum smart contract called "The DAO" [1] had a loophole that let an attacker extract a third of all the funds.
But a lot of the developers and miners had either lost money themselves, or had friends who'd lost money, or felt the embarrassing incident was devaluing their own Ethereum holdings. So they decided to allow takesies-backsies.
There's probably a philosophical lesson there about power and who the rules really apply to.
I don't think this counts as takesies backsies. This incident clearly followed the code is law principle, the whole point is that a majority forms the chain of truth. In this case, a majority decided to splinter and use a different chain where the incident never occurred.
As far as I understand blockchain, that is the system working as intended. Some nodes choose to run Ethereum Classic and some choose to run Ethereum. Isn't that the whole point? Decentralisation?
The DAO incident was a special case. It was only sane to do the rollback because the stolen funds were time-locked up for 28 days.
Ethereum never did it again, rolling back hacks didn’t (and couldn’t) become normal policy. IMO, they shouldn’t have made an exception, as it set a bad example.
I’ve seen a few other small projects attempt to do rollbacks since, but it usually turns into some kind of mess. In most hacks, the coins aren’t time-locked and quickly get laundered through smaller exchanges (and other services) which act as mixers. The stolen coins end up in the hands of a bunch of innocent people, and the rollback then causes way more harm as those users lose their coins.
The unforked variant of the network was kept alive for years. Why didn't it prevail over the forked variant?
I vividly remember a number of discussions/debates during that time (including on HN). I was more favorable to cryptocurrency in those days, and one of the things that contributed to my disillusionment was watching the people deepest and closest to it rediscover financial regulation from first principles, now that it was in their interest.