I don't know, it's pretty well known that "you can't fix stupid."
I'll take a motivated capable person and teach them skills in a new area, but just being motivated alone isn't enough. Many incompetent people are highly motivated and completely unaware/in denial of their own incompetence.
Most people can be motivated very easily by throwing money at them.
Admittedly this doesn't work for everyone (many also need other factors) but I'd say that covers roughly 90% of the skilled population.
Now teaching a motivated person a complex skill is a completely different story. Yes, money (and lots of time) can help there, too, but the scales are not normally realistic. How long does it take to turn a given, motivated person into a great programmer, even assuming an unlimited budget?
I think it's easier to transform a skilled person into a motivated person than the other way round.