[simulo]

I agree with the "single people can create good software without involvement of a UX expert". That does not only apply to UX experts, but any other expert role (You do not even need a person who sees themselves as a programmer; a person using Excel, Access, Godot… might create something useful).

A lot of roles and best practices are for making software creation work in large organizations.

I disagree with the "dumbing down" idea: "old UX" (90s, early 2000s) focussed a lot on beginner-friendlieness and at this time a lot of people might have seen this sofware as being "dumbed down" from its predecessors. Menus e.g. are a staple of making GUIs more discoverable than command line interfaces, and at that time there were already criticism that urged for building more efficient text based interfaces (See "canon cat" and the "anti mac interface")