Regulatory change, 3rd party API changes, new financial products (often arising out of the regulatory changes) all require ongoing development.

Plus I don't know about you, but my bank's website and app are a hot mess. In theory I suppose they could be feature complete, but in reality, nope.

So, just visiting Earth, or are you here to stay? :)

I've worked for banks and while there's certainly plenty of unwarranted churn the notion that they're done and the dev team can go home is ... hilarious.

Edit: addressing your comment in an adjacent thread, a box to keep your money in (or, canonically, a sock under the mattress) does not need to offer/support:

- Debit cards

- Credit bureaus. Yes, even if it's just a deposit account and no, this isn't optional.

- Know Your Customer (KYC) regulations

- Anti Money Laundering (AML) checks

That's before you get into other account types, offering credit, currency conversions and the zillion other things that sock doesn't have to do.