Rewarding the worst worker with upskilling and payrises

Why is it that the hardest workers get treated like absolute garbage and the worker who does barely anything, rubs shoulders well with the managers only, gets upskilled and promoted while you do THEIR work for them and it is all swept under the rug like them doing NO work never happened….ah I can't and this I see time and time again happen, whhhhy?!? It just doesn't make sense to me why businesses punish their best workers, how does that make any sense at all is beyond me