If all features or options in a flight were to be bundled with every ticket, the cost per person would be outright extravagant. Free checked baggage, enough room to cross your legs, a simple meal when flying cross-country, wider seats, onboard wi-fi-- you'd be buying all of that whether you like it or not. Since there's insufficient demand for flights at that price point and the businesses know that some willing are willing to pay more (though not max price), you get the fee-for-service system. That way, those who need less pay less and those who need more pay more.
Taking it to the discussion of unbundled cable, ya, if you divide your monthly cable bill by the number of channels you get, you're not likely going to come up with the price you're going to pay per channel that's going to eventually be offered a la carte. If you pay $100 per month and get 890 channels (450 of which are duplicates of other channels in different qualities), you're NOT going to be charged 11.2 cents per channel. It will likely be sub-bundled like this:
The Super Package: $100
Base Fees: $25
(Admin, Connection, Taxes, etc.)
Local Bundle: $10
--- Antenna-based TV
24-Hour News Bundle: $10
--- CNN: $5
--- MSNBC: $5
--- Fox News: $5
--- C-Span Bundle: $5
--- Other: $5
Sports Bundle: $20
--- $5 for each type of ESPN
--- $5 for NFL
--- etc.
Cable Super Bundle: $25
--- Bravo, TLC, Discovery, Food, HGTV, SciFi: $15
--- All the Rest: $15
Premium Bundle: $40
--- HBO: $15
--- Showtime: $15
--- Cinemax (Is this still a thing?): $10
--- Etc.
Chinese Bundle: $5
Arabic Bundle: $5
Spanish Bundle: $5
In the end, if you want it ALL, you'll be offered the $100 package (First Class). If you want nearly everything (AKA every option they offer in the Coach section short of moving to first class), you'll probably pay more than $100. The real benefit is for the tightwads who want Local, 24-Hour News, and Sports. They'll pay $55 instead of their previous $100. Sure, they won't get to watch Honey Boo Boo or reruns of Battlestar Galactica on TV, but they'll get their DC Comics shows, breaking news, and follow their favorite sports teams. And for a lot of people, that's all they care about.