Most inadequate drivers don't think they're inadequate, which is part of the problem. Unless your acquaintances are exclusively PMC you most likely know several adults who've lost their licenses because they are not adequately safe drivers, and if your acquaintances are exclusively PMC you most likely know several adults who are not adequately safe drivers and should've lost their licenses but knew the legal tricks to avoid it.
From the perspective of those writing the regs, speeding, running lights, driving carelessly or dangerously (all fines or crimes here) are indeed indicators of safe driving or not.
Understand, I am not advocating this. I said I did not like it. Neirher of those statements have anything totk do with whether I think it will come to pass, or not.
I don't think it's about driving ability, besides the initial vetting.