I think the only reason for the rule right now is so that there is something already on the books if the league decides it needs to start enforcing it. They are ok with how it is being used right now, and honestly it would impossible to call a consistent line between carries vs. almost carries given how many times per game and how quickly they occur.
I'm not sure it'd be that hard. Anytime a guy does what IT does literally dozens of times in the highlight video I included in the original post -- lean back and entirely stop the dribble motion for a half-second or so before re-engaging in a particular direction after the defender shifted his balance -- you call it.
Monkhouse makes a good point that what it really comes down to is how fluid and confident players are when making moves. Rookies often get called for things because they are hesitant or overly mechanical in executing dribble moves and footwork. The quicker you do it, and the more you integrate it into your game, the harder it is for refs to call you out on it.
It's not hard at all to call obvious and egregious violations. The problem is that when you start being more strict about the rule, the borderline calls will become emphasized. There has to be a line somewhere and it's easier right now to have a really loose rule with a wide berth for enforcement.
It would be almost impossible to actually catch a lot of carries that are close to not being carries. Or refrain from calling palming violations that look close in real time. That's what I'm saying. The rule right now is easy to enforce because they don't really enforce it. Any time they do, the player really has no complaint.
You can palm the ball a lot less than IT does and have it still technically be a violation. But would you want to make that call when maybe 10% of the dribbles in a game could be borderline? How many dribbles are there in an average game?