If that happens, I wouldn't be surprised if Apple disabled iOS WebKit's ability to use custom user agent strings (i.e. all iOS WebKit browsers look like Safari

If that happens, I wouldn't be surprised if Apple disabled iOS WebKit's ability to use custom user agent strings (i.e. all iOS WebKit browsers look like Safari to servers). That's all it'd take to stop discrimination of iOS browsers by content producers. Really though, I doubt that much will happen. I imagine that only reasonably tech savvy iOS users will install ad blockers and the overall impact will be minimal, just like its been for every other browser that supports ad blocking.