People have an incentive in those cases. To improve themselves so that they can get hired at another company or in an industry with more demand.

Who pays nurses more just because they are good? In a lot of professions rates are set by governments or institutions and there is not enough competition between businesses for wages.

Any private clinic would pay the better nurse more? You can check this quickly on job-listing portals – nurse wages are in the 20000-100000k/year range, so clearly supply and demand as well as qualification are determining it. Which socialist country is it where wages are ceiled by the government?

I guess that depends on what you mean by good, but better credentialed, more experienced nurses do get paid more. Source -- my wife is a nurse.

I can tell you that there is no way I’d be doing what I do if it wasn’t for the money. I’d be developing useless keyboard firmware or some other junk no one but me would care about. It would provide minimal value to the world.