The reason I can't stand debates like this is that the "most right" answer is highly dependent on the details of the organization. Strong opinions are borne from bad experiences and people tend to generalize the patterns they've observed first hand.
A small org with a founder who has a strong vision they are good at articulating probably doesn't need many PMs. Similarly, you might find teams with engineers who are actually very user and market minded and have the bandwidth to do some of that work. Or, in the case of Airbnb, you can essentially split up the role and assign pieces of it to separate teams (which, the more I hear about it, strikes me as odd.)
At the end of the day, patterns in roles - and the PM role in general - usually exist for a good reason. There's a critical set of skills that, when done well, are very much justified and should exist as a single role - not the side project of a developer or a designer.
A small org with a founder who has a strong vision they are good at articulating probably doesn't need many PMs. Similarly, you might find teams with engineers who are actually very user and market minded and have the bandwidth to do some of that work. Or, in the case of Airbnb, you can essentially split up the role and assign pieces of it to separate teams (which, the more I hear about it, strikes me as odd.)
At the end of the day, patterns in roles - and the PM role in general - usually exist for a good reason. There's a critical set of skills that, when done well, are very much justified and should exist as a single role - not the side project of a developer or a designer.