What Austin would "trade" to keep playing isn't relevant to whether or not Vick should be allowed to play in the league after his felony conviction and jail time.
Its not like because people like Vick get second chances Austin can't play, the two issues have nothing to do with each other.
Austin has a medical condition that doesn't allow him to play, just like 100s of other potentially elite athletes blow out their knees and never make it either. Its tragic when its so close to the draft, but the same circumstances happen all the time.
The universe isn't just when it comes to who gets athletic ability and athletic opportunity.