That said, while I'm hardly a fan of MCP (judge for yourself by reviewing my previous comments on the matter), at least its security model was standardised around OAuth, which in my opinion is a good thing, albeit with a few small issues.
I personally prefer CLIs, but their security is in fact worse. A lot worse! Sure, we can now store API keys in a vault, but it's not like you can rotate or expire them easily. Plus, the security model around APIs is based on path-based rules, which aren't very effective given that most services use REST-style APIs. This is even worse for GraphQL, JSON-RPC, and similar protocols.
It is backwards. I bet we will move from CLIs to something else in about 3-6 months.