Fashion changes and some shyt will be cyclical too
I think it didnt hurt that rule change also happened around the same time Kanye and Pharell were changing the fashion wave too so polo sweaters, blazers, fitted jeans were slowly coming back into men's fashion and that made it easier for NBA players, but then formal/casual wear got mad euro centric fashion and out there lead by those guys in pop culture and then the players followed it too and it still fit under the rules of the code.
Its just they streched and trolled it out to the point where its where we are now. But you gotta remember each year people had something to say. Y'all remember when people tried to flame D Wade for wearing a cardigan and specs at the 2009 All Star weekend calling him Urkel and then that was the wave anyway?
Y'all act like people wont roast what we wear now in 5-10 years, shyt just happens