It's a rough sport and why these guys are paid annually more than most are paid in a lifetime.
That's not why NFL players make so much money.
An NFL player is among the 100 best in the world at what he does. Round the world population down to eight billion, take half of that to get the approximate number of males, take a quarter of that to get the right age range, and you've got one billion. You'd rather include just a fifth of the male population? OK, 800 million. If a player is in the top 100 out of a population of 800 million, he's in the top eighth of the top 1% of the top 1% of the top 1% in the world at what he does. And his job is in a business that attracts many billions of dollars of revenue per year.
The market obviously supports current prices for game tickets, licensed merchandise, streaming subscriptions and cable and satellite subscriptions. We complain about the prices, but demand remains high. With better tools to measure the effectiveness of advertising than ever before in history, many multi-billion-dollar companies consider it worthwhile to pay more than ever before to advertise on NFL broadcasts. As a result, the NFL can negotiate some staggering broadcast deals. With all this revenue pouring into the NFL, I want as much of it as possible to go to the players. They're the ones we're watching, the ones who create the actual entertainment by pushing the limits of how well human beings can play a sport.
And because the owners know that without these top players, they can't provide a product that's even close in quality to what they have now (and that goes back to the players being in the top eighth of the top 1% of the top 1% of the top 1% at what they do), they end up agreeing to allocating a sizeable percentage of revenue to the players (I think it's 48.8% now).
That's why NFL players get paid so much.