On the other hand, there are ways you can risk your health for money, where the reverse trade isn't possible for any amount of money. So, getting back to the article, retiring early seems like a good trade.
That's possible in some special cases, but it's also quite possible to ruin your health in ways that can't be fixed. And this is what football players are facing.
Always? No. Many health issues are actually incurable with current technology. For a simple example, many forms of hearing loss are incurable as far as we know. You can spend a lot of money on fancy hearing aids but it won't get you normal hearing again.
Old rich people can't spend money to cure all their ailments and be young again. Maybe someday, but not today. And it's not a gamble if there's no chance of success.
