Let's remember two things:
1) Injuries can happen at any age: see Greg Oden, Amare Stoudemire, and Antonio McDyess.
2) One can recover from injuries, even at 32. I feel like some people on this board are like orthopedists talking about 80-year-olds who got hip replacements. Yes, the Big Three are older, yes they're more injury-prone, and yes, it may take a little more time to recover from injuries; however, in your early 30s, one can still recover and improve.