> My 2 cents: One of the reasons why I left is that there was no longer any symbiotic relationship between product management and engineering. Product makes unilateral decisions, throws them over the wall, and engineering is expected to quit whining and just do what they're told.

Ex-Mozilla PM here, I completely understand what you mean by this and I generally agree. I'll go a step further and say that as a PM I often didn't have a choice, either, decisions were being made above me and I often found out from the engineers that they'd been told to do something different than what I'd just expended significant effort on documentation to support doing. A primary reason why I left is that I felt like my wings were clipped as PM, and that I was unable to effectively build symbiosis with engineering. I'm more technical than most PMs at Mozilla were and had a better relationship (I think) with engineering than most of the PMs did, but it was a fundamentally untenable situation to be in, where I ended up just being a middle-man, which is not what a PM is supposed to be, and it doesn't create good products or user experiences.

Somewhat ironically, I think that Mozilla needs a stronger Product organization to succeed, but that wasn't happening. If PMs are doing their job right, they are there to advocate for the users/customers and ensure that the direction of the product aligns with how people are using it. At Mozilla, it felt to me like there was a very heavy top-down approach and with some exceptions, most product features or projects were focused on enabling alternative revenue pathways without regard to how this alienates existing users. Very little of what I was asked to work on had any chance of moving the needle on market share, which was and is the fundamental issue for Mozilla existentially.