People don't need 17 streaming subscriptions. There are only so many households to sell to.
How many of those households are going to pay for a subscription so they can stream Interview with the Vampire if that's the only show they're interested in on the service? Maybe if they're a die hard fan, but they won't attract casual viewers.
Since there are fewer ads on streaming services - I won't say "no ads", because already, many of the services are including them, or at the very least, including disruptive trailers for their own shows - how do those households know that Interview with the Vampire exists as a show? On the cable TV model, AMC would run a commercial advertising the show during the airing of another show with a similar audience, drawing interest and viewers. Now it's not so simple to cross pollinate. (Anecdotally, I have a friend who is obsessed with Anne Rice and had no idea this show existed.)
You say combining the production value into a single affordable streaming service is mass delusion, I say that's the only reason it worked in the first place. The popular shows buoyed up the fringe.