iPhone users spend much more money on Apps per user - but the vast majority of advertising is not for apps. It's to buy real things.

Android Users spend similar amounts as iOS users on everything besides apps.

Even in-app purchases for games isn't "many many times more" - it's close to 2x.

Average iPhone users may be more valuable to the average advertiser when compared to the average Andoid user, but there are plenty of markets where I'd say there are plenty of advertisers who'd benefit from targetting the lower end of the income spectrum.

Only if they see the ads.