When are they going to learn? From what happened with Windows 8, we know that people always expect the worst. With Windows 8, Microsoft was in a position to let rumors fly without saying much of anything because of Windows' dominant position. But this is a clear case where the rumors need to be nipped in the bud. They're going to derail any success that Lumia 900 has had by keeping quiet about it.
If they actually have learned, and they're still keeping quiet about it, one can only speculate that WP8 is going to represent such overhaul of the hardware specs that it will be too difficult to support the existing devices. Maybe there's some truth to the rumor about WP8 sharing the same kernel as Windows 8.