Sure, but many of those Xfinity customers don't have any reasonable alternatives, whereas there are now a handful of players in the video streaming space. If someone doesn't like Netflix, they can easily cancel their subscription and switch to another service. So even though you're partially right, the subscriber count in this case is a pretty good proxy of how good the service is.
The services used to have more or less the same catalog, but it’s become more and more broken up.
To get everything you need to subscribe to 4+ services, and if you drop Netflix, you lose a hefty part of their catalog because it’s on none of the others.
I guess when someone says "it's terrible", I assume that includes the catalog and we're not just talking about the UI or something like that. You can't say Netflix is terrible, and then in the same breath praise their selection. The catalog is part of the product, especially with each service making originals now.
