I can't think of a single guard who has ever stuck in the league with a 50% FT percentage.
Can you think of one that shot that and had Lonzo's other skills? I can't.
There will always be a place in the league for a guy with his passing, court vision and ability to rebound his position. Plus, he's a good defender.
But, as I said, if that happens, he'll be a career backup and considered a bust.