I think people still fail to realize that it's not just Jinbei vs Who's Who, but Jinbei vs Who's Who, and all of his subordinates.
We just had five, vastly inferior, people hold off two Yonko's for fucks sake. Who's Who is no scrub, and he's got strength of numbers on his side. Jinbei is still looking clean, so it says a lot about the fact that Who's Who, and all his subordinates can't take Jinbei down, and not a reflection of the fact that Jinbei is still fighting against them.