I believe that if time travel were invented, its use would have to be judicious so that ripple effects, have a containment field.
For instance, if you were to go back and stop Stevie Ray Vaughn from getting on that helicopter, you would set off a massive ripple wave which will in effect, destroy our current universe.
On the other hand, if you knock out Bird in '84, transported him to the year 2150, gave him a massive dose of enhanced telomerase therapy so that biologically, he couldn't physically age until a subsequent treatment in ~15 years, and then, returned him to the exact moment when he was taken, the universe would still exist.
Then, events would slowly alter around you but the world as we know it, would still exist. If so, then I'm all for this stealth Bird treatment. Then, Bird would be healthy, fit 27 year old until he turns ~42. And then, he'd go back to aging regularly, and he'd probably retire at 45, when he pulls his back like in '88. He'll be talked about as the 2nd Kareem (player with the most longevity) but as he resumes aging, ppl won't suspect that something really strange happened there.