It seems also to be a trajectory for many job switchers or aimless types.
I feel like PM's generally tend to be the people who have the least domain knowledge.
It's like the PM is the technology equivalent of the McDonald's shift manager or the fair-weather ex-{whatever} coding bootcamper.
I was involved in a project that was literally going nowhere. Every sprint failed, the team was all over the place, and the project was way behind schedule. The company moved a project manager in from another team. She had a background in engineering and some experience coding, but not to the level of most of the team. Yet after six weeks (3 sprints), the project was back on track. Mainly because that project manager go the team to better focus on what needed to be done, and what could be done, during their sprints.
None of that required domain knowledge or deep technical skills, but it did show me the true worth of a good project manager.