In all honesty, I get just as many push notification spam message on my android phone. It's an instant uninstall trigger for me. I see it more of a push notification problem rather than an apple/ios problem. It reminds me of how popups were really useful when they first came out, until they started being used as a marketing tool.
I 100% second this sentiment. I think if users start doing this more often, and reflect this in the reviews in the app store (or if the app store could have an "% of app downloads deleted" or some other metric showing dissatisfied user behavior) that would similarly solve the problem.
I gave a one-star review to an app just for spamming me with "like us on Facebook" requests in the app. But the number of reviews it had was well into the hundreds by the time I got to it, so my effect was miniscule. I agree with you completely, but as long as we are dreaming of an ideal world we may as well assume all apps behave in the first place :/
Just saw a pitch in NYC where they said that less than 3% of their users disable push notification, so they reasoned that this means push is the notification of choice. We spoke afterwards, and it seems like outright deletes were low as well (no number here), so it seems like this sort of abuse is not punished (like I think it should be) by users. Unless we get better feedback mechanisms, this sort of abuse will continue.