There is literally no bank in my country that doesn't charge fat fees. Even credit unions want at least like 8€/month for just a starter account with online banking, plus the 1.5€ fee for each SEPA transfer, seriously. Back when I learned that this isn't standard procedure worldwide my mind was completely blown.
As for alternatives, there are pseudo-banks one might use like N26, Revolut, Wise and similar, but each one of those can at any point terminate your account for no reason, some don't even allow receiving money from accounts not in your name so you can't use them as actual bank accounts. They're not exactly a thing one can keep savings in.
From what I understand, Europe typically has postal banking that's minimal fee and should be a release valve against other banks' excess, which would for the "legit price" hypothesis.
But if it's very very difficult to start new banks, or for existing businesses to start serving this demand, that would favor the cartel hypothesis.
Haven't heard of any postal banks, but digging a little it seems like we did have at least one... which merged with a commercial bank a decade ago. Sounds about right.