This is Apple's News+ in the nutshell, so federated subscription service you're envisioning would have to compete with Apple.
I want to be able to have a non trivial level of discretion as to which writers/groups to starve and which to support. For example, being able to pick a handful of sites or articles where my subscription/views/view-time don't count towards their bottom line. Or we could set aside 30-40% of subscription cost to distribute based on the the proportion of some active user action for like Medium's claps or some other rating.
At present the economist/ft are the only publications that haven't let me down in a big way and I'm weary of supporting anything else.
edit: apparently you have to use apple devices? oh heck no, what were they thinking?
That's what they're thinking.