[ilyt]

The ethereum DAO fork showed that the moment the "big ones" are hit there is not much stopping them from violating the "immutability" promise for their own gains.

Instead of few big banks there are few big mining pools deciding the fate, distinction almost without difference. And in both cases you need money to get in to the inner circle

[vba616]

Anarchy always falls apart. I don't know why anyone would think that's a historical accident rather than a logical inevitability.

[mattdesl]

There are no mining pools in Ethereum today. The chain is "immutable" only up to the point that the social layer wants it to be; majority users can change the protocol as they see fit (see EIP 1559, PoS, and other forks).