Padres only had Padres.TV and national games. They did what the Twins are doing now.
They, by the way, are the biggest success. We don't know the Arizona or Colorado subscriber counts but it was likely far less than 40k because no one has dared report what the actual number is.
Also, the Rockies could make similar geographic arguments and household reach. Probably moreso than the Twins given the larger populations they expand out to in their region. It's quite possible the Rockies didn't even clear 10k.
Availability is great, but casual fans aren't going to pony up $20 a month when there are alternatives that cost zero. Not to the tune of 60k at least. You'll get your diehards and that will probaby be it.