>5. Decisions, and what you prioritize, need evidence
This. In my experience PMs' features are driven by not evidence but "lets try this stuff out" and "hypothesis" causing a ball of mud on the engineering side to ship stuff fast to impress the stakeholders.
I don't generalise and I also have seen PMs to be brilliant - but is more an exception than the rule - some PMs I've worked with they had very strong analytical skills, engineering knowledge and domain knowledge + skin in the game - if a feature has turned out to be crap they have the guts to kill it