From a PM perspective, the main differentiator between an engineering team and AI is "common sense". As these tools get used more and more, enough training data will be available that AI's "common sense" in terms of coding and engineering decisions could be indistinguishable from a human's over time. At that point, the only advantage a human has is that they're also useful on the ops and incident response side, so it's beneficial if they're also comfortable with the codebase.

Eventually these human advantages will be overcome, and AI will sufficiently pass a "Turing Test" for software engineering. PMs will work with them directly and get the same kinds of guidance, feedback, documentation, and conversational planning and coordination that they'd get from an engineering team, just with far greater speed and less cost. At that point, yeah you'll probably need to keep a few human engineers around to run the system, but the system itself will manage the software. The advantage of keeping a human in the loop will dwindle to zero.