I'm not trivializing the long term consequences of these injuries and dismissing their impact on our beloved football squad, but these guys are very aware of the risks and are compensated extremely well. Beyond what 97.3% of us will ever see. Way beyond.
Also, it greatly influences the influx of new talent into the league and/or spotlight. Just picture the old, slow zebra at the waters edge. It's hard to watch as the croc pulls it under, but in the grand scheme of things, completely necessary. You feel sorry for the zebras for a while, but the balance to the whole system is maintained in a way. e.g. Sorry Bledsoe, you're on the Bills now, allowing room for another organism to thrive.... For 15 years... Thanks nature