An AV codec isn't a weapon to lock developers into your platform while wasting millions of dollars and thousands of man hours on pointless api ports. There are too many implementations of encoders / decoders for the various formats lying around to get away with that. Its not like they didn't try with Quicktime in the past (ish? .mov was just a crippled .mp4), but that never really made them any money I don't think.
