They may be living lavishly right now, but I'm sure not all of them were at the top of the food chain to begin with. Yes there are people who had their ways bought, but look at upcoming NBA Superstar Giannis Antetokounmpo. 5 years ago he was selling nick knacks on the streets of Athens trying to help feed his family. Now he's one of the biggest (literally) names in the NBA. These players that get upteen million dollars are the superstars. The best of the best. There are players in the MLB like Scooter Genett who wasn't getting the superstar contracts, only making ~500k and a somewhat mediocre player, never really playing for big name teams (Milwaukee and Cincinnati) but is having a career year and will most likely be picked up by a big name team with a huge contract.
And then we have Allan Iverson's of the world. Incredible talent, huge contracts and endorsements out the wazoo. Dude ended up blowing through all of his money and honestly would be on the streets right now if it weren't for his deal with REEBOK. Which I still don't fully understand.
There are fighters in the UFC that can get huge fight deals but still not be good enough to quit their day jobs. About a month ago there was a fighter whomst I cannot remember the name of off the top of my head, that won a fight in kind of bizarre fashion, was kicked out of the UFC and now has to continue his day job for "the rest of his life." Yeah he got a big chunk of change, but it won't last him his whole life, and probably won't be wearing any Gucci suits anytime soon.
And we don't even know what goes on with these athletes behind closed doors. They go through so much testing, take so many supplements and pump plenty of unnatural things into their bodies to get them to their peak performance. Most of it is natural but everyone does whatever they can to get the edge. The more I watch professional sports the more I'm glad I'm not a pro athlete. Even golfers put so much strain on their bodies they're going to be in a lot of physical pain down the road. You just gotta find the tradeoff.