Pro football players have to earn a life's salary in a few years before they get worn out. $2 million over 50+ years isn't really that much.
Heck, if I could have gotten a couple million dollar head start in life by working on my hobby once a week, I'd take that even if I had to delay a regular career by a few years.
"According to Sports Illustrated, 78% of NFL players are divorced, unemployed, or bankrupt two years after leaving the game, and MSNBC reports that one in four NFL players live paycheck to paycheck" [1].
Most athletes do not invest wisely, and often lack the experience to handle large sums of money [2]. Are you so sure that you'd be the exception?
[1] Slideshow warning: http://www.complex.com/sports/2012/04/six-reasons-why-pro-at...
[2] http://www.huffingtonpost.com/don-mcnay/like-lottery-winners...