Not because people can't afford it, Americans happily paid $120 for cable, but simply because the balkanization throws convenience out of the window and nobody wants to deal with that.
1) Subscribe to only one or two services at a time. Binge the stuff you missed while you weren't subscribed, then drop it and switch. Works if you don't care about discussing stuff with people as it airs. Less good if many of the services penalize short-term subscriptions.
2) Abandon digital-delivery TV/Movies. Use the friggin' library, and spend what you would have on streaming buying discs instead. Downside: storing stuff sucks, library less convenient than streaming but honestly we're talking about giant wasteful time sinks to begin with so oh well.
3) Just pirate. If there's stuff not commercially available that you want you'll be doing this anyway, and it's barely more effort/expense to maintain the hard drives, backups, and playback infra for a handful of your shows/movies than it is to do so for all your shows/movies.
I wonder if companies like HBO plan for this type of usage and schedule their shows to start and end at times that would necessitate paying for an extra month of service.
Disney is banking on people believing they deliver value for the money. For parents of young children, maybe they do. Certainly more than "nobody" will agree.
Addendum: I think you updated your comment as I replied with the note on balkanization, but subscriptions are "set it and forget it"--it's why paper magazines still exist.
> Time Warner (NYSE:TWX) CEO Jeff Bewkes announced that the company surpassed 2 million domestic HBO Now subscribers during the company's fourth-quarter earnings call. He later added that subscriptions tripled in 2016 compared to the end of 2015, which implies closer to 2.4 million subscribers.
That's a fraction of Netflix's US subscriber base, but it's not nobody.
People did deal with it. Which is why they're expanding it.