This was true already before AI code generation, but AI code generation means the definition of “fast” has shifted like crazy. An experienced engineer can now build in an hour what would have taken them a week.
But it (right now) does nothing for the confidence about being correct - you still have to put in the extra time to ensure the software is correct to your desired degree of confidence.
Unfortunately for people who like their software to be correct (stable, performant, bug free, etc), it seems like way too many software developers right now are happy to take the gains of the former but ignore the tradeoffs of the latter.
(at the same time software quality for mainstream consumer goods like the kind of thing OP complains about in their post has been down the drain for a long time now, and it seems likely many of the examples they give are pre-AI)