For customers Windows RT promises much and fails to deliver in the most comprehensive manner.
The promise of Windows on a tablet is that it will operate like Windows and run Windows programs. Windows RT doesn't do this and so the Surface is compromised. And if Microsoft can't make Windows RT a success why would other OEMs waste R&D and marketing dollars trying to do better? Its bad enough trying to sell one version of Windows 8 in the current climate, never mind two.
Microsoft made a fundamental mistake with the launch of Windows 8. It gave customers the impression that RT was 'Windows-lite' - designed to run on tablets but otherwise the full experience. This doesn't make any sense - especially when Windows Phone 8 was being developed alongside and, with a little bit of tweaking - could be made to work quite well with the medium resolution screens that characterise Windows RT tablets.
The benefit would have been twofold - developers would have had a much larger customer base to develop for and consumers buying Surface-like products would have found a much greater choice of applications available to them on day one.
In fact had Microsoft set the minimum resolution of RT in landscape mode at 1280 x 800 pixels users would have been able to multitask three Windows Phone applications across the screen - a huge selling point when up against the iPad and Android tablets. Even better, imagine a live hand-off between those apps on the phone and tablet, moving from one to the other seamlessly.
This could have been the killer feature that boosted both Windows Phone and tablet sales. Instead it was a missed opportunity.
Microsoft are rumoured to be extending the range of screen resolutions supported by Windows Phone to allow its partners to move into the Phablet space. Perhaps this would be a good time to rethink the Surface and Windows RT too...