Both already exist.
Apple already has the iTunes store in which people can choose commercial-free shows and has for years now. Problem: we don't want to pay for that; we want it dirt cheap.
DirecTV/Dish/others have services where you can hide all of the "useless" channels you don't want and only display the ones you do want in a "Favs" guide. This way the subsidy dollars made from commercials (including most of that subsidy made from commercials running on channels we never watch or while we sleep) keep contributing to the pot. Problem: we instead have this delusion that an Apple can plug in, offer us just the channels or shows we want for for a fraction of what we pay now. Nobody else- Apple included- is interested in turning that delusion into reality; they all want to make MORE money, not less in any "new model".
I'll guess that neither of those would be what you want and I'll further guess that what you want is closer to the usually-spun dream of "everything I want, commercial-free, for a tiny fraction of what I pay now". Problem: we're not going to get that.
If there's ever some kind of al-a-carte option other than what we have now in iTunes, I fully expect the math to work that we'll get our 10 favorite channels (or shows) for about 30% MORE than we can our 10 favorite channels + 190 channels "we never watch." And then we'll probably be clamoring for some kind of bundling with discounts and subsidies to try to get back to how it "used to be."