9-11 SB on my Bigs is not so low, or you think it should be much more for stop the LI?
So how would you expect your 9-11 SB to stop the 17-20 IS of your opponents when you play 2-3 zone?
The SB has not so important role like IS, ID, RB, or do you think in another way?
Except, they haven't been saying this "recently" but more like 8 seasons ago. And 8 seasons ago people were saying the same thing you are saying now. And in the meantime almost every meaningful trophy has been won by a LI team. Players with 15-17 sb exist as do big men with 10 OD and their owners haven't exactly been thriving.
Defence is cheaper than attack, but... nobody trains it