If Ethereum successfully migrates to proof-of-stake then it won't be bottlenecked by proof-of-work any more ;-)
It may end up rebuilding the current regulated banking system. But if the regulated banking system and the unregulated banking system are sitting next to each other using tokens that are interchangeable with smart contracts, that seems like it could be useful.
If a regulated banking system mixes with an unregulated banking system everything becomes an unregulated banking system.
Also proof-of-stake has been promised for so long I would be embarrassed to talk about it if I worked at the Ethereum Foundation. Delivering things that work isn't their strong suit.
It may end up rebuilding the current regulated banking system. But if the regulated banking system and the unregulated banking system are sitting next to each other using tokens that are interchangeable with smart contracts, that seems like it could be useful.