Google has huge interconnect and exchange deals and dark fiber all over the place. It’s hard to explain just how much free transit and connect Google has to ISPs, and how preferable their deals are for delivery. They are a MASSIVE pipe of extremely low cost Internet.

Since the main cost of video is streaming and the pipe required to deliver that streaming, they have an insane moat built because of it.

That is why. There are a lot of other explanations, but that is really why.