Putting on a PM hat is something I've been doing regularly in my engineering career over the last quarter century. Even as a junior (still in college!) at my first job I was thinking about product, in no small part because there were no PMs in sight. As I grew through multiple startups and eventually bigger brand name tech companies, I realized that understanding how the details work combined with some sense of what users actually want and how they behave is a super power. With AI this skillset has never been more relevant.

I agree your assessment about the value of good PMs. The issue, in my experience, is that only about 20% (at most) are actually good. 60% are fine and can be successful with the right Design and Engingeering partners. And 20% should just be replaced by AI now so we can put the proper guardrails around their opinions and not be misled by their charisma or whatever other human traits enabled them to get hired into a job they are utterly unqualified for.