As for AI-written code, I wouldn't fly on a plane controlled by AI-designed and AI-tested code, but much of development is busy work, not problem solving or design. AI excels at turning a protocol spec into a parser for example. I'll take that any day. AI excels at finding stuff, particularly non-code, thesis-level ideas for algorithms and also at about the same level, what's been shown not to work when solving a non-deterministic problem.
If we're lucky, AI will fill in after exposing who is only doing busy work and who is creating.