Multi-channel content

I am in the process of writing a masters paper [1] on the topic of
device independence.

I thought I should write to this list, to see if anyone shares my belief
that we do NOT have to have :

"multi-channel content, i.e. services available for various groups with
various browsing equipment"

I feel a little on my own here compared to fairly large amount of
research on the opposite end. I wonder if someone can give me some words
of encouragement, or tell me where I have gone wrong.

Right now, I believe a well designed XHTML document should be accessible
by anyone on any device. I also think CC/PP is a waste of time.

[1] http://www.cs.helsinki.fi/u/hendry/work/thesis/topic/report.ps