A great way to solve for this in B2B, is to hire a customer and train them as PM. They will hit the ground running much faster to bridge the gap.
That is to say, the only customer we could convert to a PM was one who was fundamentally bad enough at his existing client side job that he was OK capping his income at 25-50% of his potential.
It also doesn't give them any training in how to PM.
They should just be someone technical enough with enough people skills and familiarity with user use cases to bridge the gap.
Managers of any company that think they can't afford to lose a single employee are doing something wrong and should google "key man risk"