I think if you took away the three point shot now it would just destroy the game. Athletes are so much more athletic, so much smarter (on the court), and too well coached. If a defender didn't have the threat of a 50% better shot behind that line, they would crowd the paint more (making inside play impossible). Superstars like Stephen Curry would be completely neutralized because who cares about some guy shooting 40% on a two-point shot. If it didn't completely neutralize all offense (no spacing, no runouts from long rebounds), it would almost inevitably become an unwatchable foul-fest. Guys would just be driving into crowd after crowd of defenders, and the refs would be on the hook for figuring out who broke the rules.
I think it's also important to remember that low scoring games don't mean good defense. Most often, low scores are about pace. And as fun as it was for my personal favorite team to grind others into dust, I won't pretend that anybody outside of Michigan thought the Pistons were legitimately fun to watch.