Well, that's an interesting take. But it seems the easy way to lower the value of taking a three-point shot is to eliminate the three point shot (or, as the NBA would almost certainly prefer, only allow shots outside the arc to count as three points in the final 2 or 3 minutes or whatever - the NBA wants teams to be in reach at the end of games). Your suggestion would encourage deliberate fouling, probably result in increased flagrants and altercations as players get too enthusiastic fouling, result in more game stoppage time...there are some interesting strategic points but I don't think it sounds like the best idea in toto.
I have a hard time believing the NBA would eliminate the 3 point shot entirely; it would alienate more money than it would excite. And I don't think things are yet that dire for the NBA that they'd consider something so drastic. (I think that the rise in 3pa is actually correlated with a rise in revenue, so any changes to the rules on this would probably require the NBA to crash, or would require subtlety )
One FTA per 3PA probably wouldn't upset many people by itself. And as a relatively subtle rule change, it's hard to predict exactly how teams would figure out how to play it. But I think some things will prevent it from being cheesy;
- Players can still foul out, so it's not like it's a substitute for defense.
- If there's a lower expected value for 3PAs, then teams are going to shoot fewer 3PAs, so the chances to deliberately foul will decrease as the tactic becomes more effective
It's a convention that defenders should foul instead of allowing a layup, and players seem (mostly) accepting of hard fouls in that circumstance. There would be an adjustment period, but eventually players would get used to it.
I think the stoppage time will be a wash; maybe there'd be more fouls, but with only one (terminal) FT per foul, the game might move even quicker.
Also, my hope is that by decreasing the value of a 3PA, it might enrich the basketball ecosystem with players that excel in the midrange, as there'd now be a competitive reason to take those shots.