Well.. you know, Bitmain couldn't have used the power against Segwit forever. There's no chance anymore to go against it. It's here and it's gonna stay active from now on.

Even if he would have been able to take Segwit down for this period... There are more than 10 activation periods left. That means he would have to keep his stuff on for months, which would turn into a big, BIG failure for him.