Grizzlyjin
Supersonic, idiotic, disconnecting, not respecting, who would really ever wanna go and top that
I wouldn't assume there's a big fanbase. I would assume most of the show's fanbase are people who read and write TV blogs. The bubble is nice, and the people in it have good taste, but there's no need to project beyond that. For what it's worth, literally no one watched Mad Men; its popularity was entirely a phenomenon of well-connected literate educated people talking incessantly about it while ordinary humans never bothered. Its finale, the most-watched episode ever, got a 1.1 in the demo and 3 million overall viewers. Average ratings were around a 0.4/0.5 for most of the show's run, sometimes less. But if you just took an impression based on criticial buzz and awards and bloggers, it would seem to be one of the biggest shows on TV.
Note that the most logical extrapolation from this would be "wait, why revive a 25 year old series that was impenetrable the first time around if no one cares?" and I don't have an answer to that either.
That is almost certainly what it is. These are shows for writers.
I think it's still a win for Showtime. What do they care if people are still signing up? I started my Showtime subscription for Penny Dreadful but that lead to me getting back into Homeland, which I now still subscribe for. Come for one thing, hope they stay for the rest.