You are suggesting that Apple wouldn't touch ads, but that's exactly what they did with IAd
And more importantly, iAd seems to focus on advertising apps themselves (like a game ad inside another game). This is a far less intrusive model than a general-purpose search engine (where you find all kinds of advertisers).
They tried to launch premium ads...
The launch definitely was not focused on "small developers" too.
While keeping 40%, i don't think they were generous at for the "small companies" ;)
So I really don't know how you can get to that conclusion.