Still, medical coverage in the US generally sucks and I would hate to be saddled with medical bills following being a career athlete and no longer having the big NFL salary. I can't imagine it's happy fun times.
But this is not because they don't get enough money and more money would fix it (well, it it could be $trillions then maybe but it is never going to be that). It's because they don't have the right tools (widely understood) to manage their money properly, and their income structure is unlike income structure of many regular people (huge sums for very short period, then nothing - as opposed to much smaller sums over much longer period) and it requires very unobvious actions to make it work. If you have literally millions of dollars in your account, it's very hard not to buy some nice expensive things - even if you know you'd need those millions for decades to come, your brain doesn't really work this way. Some people manage it properly and create brands and side businesses for themselves or just live with reasonable expenses and are ok. Some spend too much and end up broke.
This "no experience managing a budget" stuff is hilarious, you don't need special knowledge not to blow millions. It is not hard. Let's call it what it is for most people - being trash, living extravagantly, and not thinking about the future. It's far more about character than about financial knowledge.
Achieving this goal usually requires you to avoid serious brain damage. Repeated concussions and wisely living off the wealth you acquired in a few short years while still very young by managing it extraordinarily well for decades to come are probably mutually exclusive.