Sometimes preventing fragmentation of the network is more important. A mobile operator can't, for instance, use licensed spectrum to run a service that doesn't interoperate with others or with emergency services - even if it's free.
If Verizon were to sign up for this, it would fall foul of FCC's rules too (it is clearly paid prioritization when all websites that don't pay are blocked.) It's not for nothing that net neutrality laws in a bunch of countries (Chile, the Netherlands, Brazil and probably a few more) explicitly forbid zero-rating.
If Verizon were to sign up for this, it would fall foul of FCC's rules too (it is clearly paid prioritization when all websites that don't pay are blocked.) It's not for nothing that net neutrality laws in a bunch of countries (Chile, the Netherlands, Brazil and probably a few more) explicitly forbid zero-rating.