Micah Dubinko mentions with a tone of surprise, both in his article Is XML 2.0 Under Development? and in a subsequent blog post, that despite the poor browsers, XHTML adoption is still farther ahead on the mobile web then the desktop web.
In my opinion, it’s the exact opposite. It’s because of the poor browsers on mobile phones that XHTML is ahead on the mobile web. For a mobile developer, there is a clear reward in going with XHTML. You are much less likely to have your page break on a random phone if you stick to XHTML MP than you are if you go with HTML. On the desktop web, there is no such reward. In fact, if you make a mistake somewhere, your page is much more likely to break if you claim in the content-type or doctype that it is XHTML. There is no reward on the desktop web in going with XHTML apart from a general feeling of having upgraded to a later standard.