I
I disagree with the statement that "... iOS has some built-in support but third party options are limited, and often cumersome (sic) ..."
iOS has AdBlockers which are supposed to operate in the same way that those available for the Desktop (just search for adblockers). They are new, and so for the most part poorly implemented but they are there.
An Adblocker for iOS that actually blocks Ads *inside* apps would work better because most ads for iOS are inside the app and presented to you by your local neighbourhood *developer* so you have them to thank for the adverts, not the advertisers themselves. For instance, eBay's new app (which it's pushing people hard to adopt over it's original iOS app) has built in adverts. The whole purpose of them creating the new app was so that they could present people with advertising.