Product management and project management are very different career tracks (or at least, they should be); it's much more common to find technical backgrounds in product managers than project managers. I'd almost go so far as to say that if a company has project managers working with software teams, I'm not really interested in working there. Some situations do benefit from it, but my experience is that it's usually a sign of either a company that doesn't understand software development, or such a messed up situation that it will be impossible to succeed.
I'd say that the best project managers I have encountered were non technical. They were able to defer to technical people when needed but always kind of kept an arms length from it and it worked well.
The best project manager I've worked with was a lady in MissionCloud. She was PM of the consulting project that mission did for our startup. I wish I could find someone as skilled as her.
