Writing code is easy compared to supporting, debugging and enhancing code. AI is much better at "greenfield" coding where you start from scratch, either on an entire app or a new feature. For anything non-trivial, it is terrible at debugging. At best it is a super-rubber-duck that is nice to talk to that might have a few words buried inside screenfuls of text that help a human realize what might be going wrong. We're still in the honeymoon phase, where AI has only written new stuff and hasn't been around long enough to have to support code with tens- or hundreds-of-thousands of LoC.