People are doubting because of the public statements made by Sony employees. I understand that people are saying it is being worked on off-the-record, but if that was enough to consider it a done deal, then why isn't Sony willing to say anything publicly that commits itself to bringing those features? They are willing to commit themselves to other features like Suspend, but not to MP3 or DLNA. Why shouldn't this be seen as an indication that they are less than 100% committed to those features coming out in the future?
It concerns me that these back-channel rumors about Sony's future plans are being used to damp criticism against the publicly-stated policy. If the consumer criticism dies out quickly, prior to any sort of public promise of these features arriving in a future update, Sony may view that as an indication that consumer demand for those features was not actually as strong as it initially appeared, but rather that this was more of a flavor-of-the-week complaint. Then they could subsequently deprioritize or even cancel the development of these features.