Correction. It's the same "niche" Microsoft wrote _some_ software for, and had their OEMs deliver overpriced, crappy devices. Dell's tablet was around $2200, and had the specs of a $700 laptop.
And not to mention, outside of a few apps like OneNote, using Windows XP/Vista/7 in tablet mode is not a super pleasant experience.
I don’t see digitizers and styluses having any kind of mass-appeal. I cannot imagine any kind of plausible scenario for that. This is not a feature you can sell (except to a niche).
The Surface has to succeed or fail as a post-iPad tablet, not on tech specs no one cares about.
Drawing, and notetaking. Especially the latter. Having a digitizer and actual pen is far superior to capacitive devices for note-taking, since it more closely replicates actually taking notes.
And not to mention, outside of a few apps like OneNote, using Windows XP/Vista/7 in tablet mode is not a super pleasant experience.