Seems inevitable. CPMs drop, buyers get desperate, ad units get invasive. Consumers hate invasive. Ad blockers emerge as a relevant biz category, so there's money to be made.
To Apple, by allowing ad blockers (and other Safari filters I presume), they can deliver better experience on those gross websites, and make a little money for a new category of apps (similar to the keyboard app stuff). Conveniently, this hurts web-based publishers, but hey, it's what the users are screaming for, and everybody else does it.
Developers think: oh great, something new to sell. Apple does want us to have control! And to think it only took 9 years.
Publishers, seeing a progressive drop in numbers, must explore other models. Apple News will probably feature micropayments of some kind which would be very convenient.
I can't see how any of these trends can be reversed, unless micropayments on the open web somehow caught on. With Bitcoin's endless drama that seems unlikely. Can you see any other conclusion?
A future app-based web really bothers me.