It shows PT Barnum as a poor kid and then a poor adult who can't even buy his daughter ballet shoes. But then, something happens. The most important thing in determining if someone deserves wealth: he comes up with An Idea. His idea is to take people who are "freaks" and sell tickets to see them.
It becomes a success and then it shows Barnum buying a massive mansion and he's clearly now super rich, which afaik is pretty close to the truth. What about the circus performers? Did they get wealthy too? Nope! Certainly not in real life but not even in this movie, either. In real life I doubt the performers even made much above a subsistence wage. But in the movie, money isn't important to them. No no, they only care about "coming out from the shadows". Barnum is the one who deserves riches because he had The Big Idea and he takes risks.
This movie is a good microcosm of understanding how Americans view wealth and business. Wealth is only "bad" if you're old money and you outwardly show that you think you're better than everyone else. But if you're an "entrepreneur" who comes up with an idea, it's really all about you and you deserve wealth. The people who actually make it all happen? Nah fuck 'em. It was the brave and noble entrepreneur who took ALL the risks and had the good idea that one time, he deserves unimaginable wealth.
I believe some of the more famous sideshow performers were able to make a good living, and sold photographs of their likeness or made appearances aside from the sideshows to supplement their income. But that experience was far from universal, and certainly none were ever as wealthy as Barnum. Not a small number of sideshow performers were developmentally disabled or didn’t speak English and were blatantly being exploited.
I studied the history of circuses and sideshows in college, and it completely turned me off the circus. Maybe some small circuses treated their animals and employees better, but the industry itself was just the quintessential capitalist machine, churning through bodies for profit.