iAds Should Fail
Apple's iAds program hasn't done very well. They promised to make advertising not suck. It's worth noting that the goal was to make advertising better for device owners rather than advertisers.
I love that the iAd program isn't doing well, because it means that Apple respects their device-buying customers more than their advertising customers.
Advertising always complicates business models by adding conflicting demands on the producer. To the extent that ads are better for device/app/blog customers, they are generally worse for advertisers. Advertisers almost uniformly believe that intrusiveness and pushiness is effective.
So Apple's goal of making ads better for device owners is not likely to thrive, because advertisers won't want to pay a premium for something they believe to be less effective. This could have resulted in two outcomes: Apple could increasingly make ads more intrusive and pushy in order to make the iAd platform successful for advertisers, or it could wither on the vine, because they refuse to put out distracting, pushy ads.
The fact that the iAd platform sucks means that Apple is committed to serving their device customers more than advertisers. And that's the best result I can imagine.