This all sounds nice, but developers/designers rarely want to do PM work. The PM position is as much a creation of developers who don't want to interact as it is management.
Even developers that do don't want to spend all day in meetings. A PM can help there.
When they realize it's more soft skill oriented, endless meetings, power point deck after power point deck, stakeholder after stakeholder, and 1 hour left to code, they finally get the picture.
I was once that developer, thinking I knew what was best for everything. I scoffed at management and project managers. Now I know the real truth - their job is way harder than it seems.