In fact, Audio on Safari-iOS has been intentionally crippled by Apple (its not "un-implemented" features, its intentionally-not-implemented features") so as to prevent any disruption of iTunes revenue stream from Audio-playing websites.
That's not a fact. However, the fact is that HTML5 audio is indeed crippled on iOS because you need a user action every time you want to play some audio, which also leads to lots of lag. However, even if that would be correctly implemented the Moog synthesizer would only be possible if they added the Web Audio API that Chrome and Firefox have.
That sounds like intentional crippling. Apple haven't done that to avoid annoying people, they've done it so you can't make games with sound on the iPhone.
They haven't removed the Geo Location API from Safari because it means websites could steal your location. They added a dialogue to ask if you want to allow them to use it.
I really don't think that's the reason. Not only does Apple not actually make very much revenue from iTunes, it is probably more to do with audio hardware on an iphone being limited.
Fair enough, nevertheless the motivation just doesn't ring true to me. Apple doesn't cripple things to protect revenue streams. They cripple things to maintain control.