To start, I don’t think it’ll be a “subscribe or else” type deal. My assumption would be something like a forced S mode unless you subscribe.
Second, people won’t jump right away. To start, word will get around and they’ll simply not update. Then, when it comes time to buy a new computer, the average user will be possibly swayed to look at entry level MB Airs (They often go on sale for like $750) or Chromebooks.
The people who will get really pissed will be power users and gamers who will be forced to shell out money to get back features they had in previous versions of the OS.