The sad thing is that it isn't necessarily the candidates fault if aren't cutting it, some managers were MUCH better at onboarding than others. So good people were lost, some not so good people retained.
As for 10% a year pay hikes, that just doesn't work. You'll double their salary in 7 years and double it again in another 7, so with 14 years experience you think they will be 4x productive as someone new? I could see it being great for retention (problem solved!) but hard to build a business model around it.