Keep in mind, Wikipedia benefits from non-neutral networks in some developing countries where Wikipedia doesn't count towards the bandwidth cap.
It's a pretty complicated world.
Wikipedia is only on offer for (disingenous) good will.
It's coming too, because it is a great deal for ISPs (more money! Huge kickbacks for the senior management!), and a great deal for megacorp incumbent media companies who don't have to worry about any of those pesky upstarts screwing up their monopolistic business models. No more Netflix like services appearing and eating your lunch, you can effectively cut them off at the ISP.
This puts say, Hacker News, in a very bad position.
As well as any new startup that wants to compete against the major players with billions of dollars.
Already there are people strong-armed into AT&T's DirecTV Now, which is zero-rated on AT&T's wireless network. With the pitiful bandwidth caps on mobile data, how can Netflix possibly compete with that?
"Get Facebook, Twitter, and Google for just $9.99/mo!"
"Add on the video package and get Netflix and Hulu for only $24.99/mo more!"
"News junkie? Get BBC, NY Times, CNN for $7.99/mo."
The reality is of course much more nuanced than that (what's more likely is we'll see these sites being offered bandwidth cap exemptions and faster loading; not outright blocks if you don't pay up), but it conveys the message in a easy-to-digest fashion for the lay person. They're used to this already with their cable packages.
Example: http://i.imgur.com/rL33yEm.jpg