If you change phone operator, there is number portability. But changing banks is a lot harder.

The EU could do what the UK did, which is making switching bank bank account automated for people (transaction forwarding, migrating direct debit authorizations, etc.). A lot of people might switch to more competent banks. I'm stuck with Deutsche Bank in Germany, for example. Switching would be a bit of a hassle. I'd have to make sure all the direct debit stuff gets changed to the new account (tax office, various insurances, etc.) all doable but it's a bit of friction. I'd be chasing different companies with forms, emails, etc. for a while.

There are a lot of user hostile banks that deserve to lose their customers because of their ineptness. The surviving ones would probably become a lot more service friendly. That's what competition does. German banks are particularly bad. I've lived in other EU countries. So, I have hands on experience with more competent banks.