The NBA rule has been changed
True, that's how the Celtics brilliantly got Larry Bird. But the rule was subsequently altered. If a top collegiate basketball player decides to return for his senior season, it's not like the same tactic can be utilized today. The player must be eligible in THAT particular draft, regardless if he's already signed a pro contract elsewhere. You would have seen Ewing, Sampson and countless others who finished their eligibility selected a year or more early if that rule had remained. Remember, Larry Bird was a 5th year guy, after starting at Indiana for a week or so before bolting back to French Lick.
BTW, a girl I know in Las Vegas used to be a drink cart girl at a golf course Bird plays regularly in Indiana. She tells me he bought and consumed more beer than anyone else by far. When she wandered away from his foursome, Bird would scold her upon return; "What are you trying to do, get me sober?"