It's because they do not reap the benefits of ipv6 nor do they bear the burden of continuing to use ipv4. Those sites are big enough that they can simply rely o

It's because they do not reap the benefits of ipv6 nor do they bear the burden of continuing to use ipv4. Those sites are big enough that they can simply rely on the fact providers ensure their customers can reach those sites. They could be using the OSI protocol and providers would still find a way to tunnel their customers to those servers. The cost of ipv4 is ultimately being paid for by customers in the form of higher fees for their internet subscriptions. And this is exactly a case where the government can help the market operate more efficiently by demanding standardization.