A lot of companies have the idea that if you work your ass off, neglect your personal lives, and perform the work of several individuals, that you'll be “rewarded” with promotions, incentives, and so on.
So is it:
a. Do the work, get the promotion; or
b. Get the promotion, then do the work?
Simple answer. Employers have destroyed the goodwill they had with employees by lying every chance they get while stealing from us (see inflation wage increases, fair wages, etc) in an effort to produce blood from a stone.
Do employers not realize how much more productive and efficient we'd be if our needs were met?
We as humans actually get dopamine from doing things to help others. It feels good. That's why people do good things for others.
Sure, as a company, there is a bit of risk involved with promoting the wrong person first. But generally, through training and taking care of people, you can recoup the shit out of your losses with having people who generally feel cared for and needed.
If changing my salary from $50K to $95K costs you $45K, but nets you $250K in productivity, it's a no-brainer! Or damn sure as hell should be.