Yes, some of them have done well with other ventures. But the stars made life changing money.
The hundreds of others who didn't?

For example. Minimum salary for baseball players is going to be close to $650k/yr. Imagine you are a fringe guy, play 2 years, make $1.3M, get cut and don't make the Show anymore. That's life changing money. You can spend the next 5 years figuring out what you want to do.

The minimum salary was $30k in 1980. 2 years of fringe ball and you made just above the median salary of $21,020. Median salary today is $44,225. Quite a difference in where those fringe players rank in today's wealth society vs. 1980.