I challenge the idea that there is no skill test for PMs, though - take a PM interview at a serious product company some day.
And the PM role is of course more than just delivery. If they dropped dead the product would still get shipped. But then what? Someone would need to talk to customers, dig into data and figure out the roadmap. Other people can do it, but in a sufficiently complex company you might as well get people who are good at it and want to devote their time to it.
I understand why some engineers don’t like PMs. But it is exactly the same reason as why some PMs (and C-suites) view engineers as fungible resources who waste time on abstractions instead of shipping, and pad estimates and refuse to discuss practical tradeoffs to move quicker - it’s an unfair generalisation based on bad experiences.
I just think more respect all around wouldn’t hurt.