They've reached a market position where NN doesn't really impact them much. They, now, have the cashflow to pay their way out. They can pay, smaller companies cannot, thus cementing their position in the market. Absence of NN, in an indirect way, helps them competitively by constructing artificial barriers to entry without taking the heat.

Sure ISPs have their own equivalent offerings, but dealing with one or two competitors in an area is easier than dealing with a couple of them.