That's because the split between the two operating systems has nothing to do with location, or who the user is, and pretty much everything to do with hardware configuration. Namely, if your system has a dual-core processor, a 256-Mbyte graphics card, and 2 Gbytes of memory, you can use Vista. No graphics card and less than a gig of memory, you gotta go with XP.
I'm going to get into a bit of trouble with Microsoft on the above, because Microsoft lists the hardware requirements for running Windows Vista Premium as: A 1-GHz processor, 1-Gbyte of system memory, and 128-Mbytes of graphics memory. However, in my experience, a 1-GHz processor isn't even fast enough to run a decent XP set-up anymore. But the question is irrelevant, because $75 will get you a 3.2-GHz Pentium 4. As for graphics and memory, Vista will indeed run with the specs Microsoft states, but you'd be better off with the upgrade. My Vista system has 1 Gbyte of RAM, and my usage meter hovers around 75% most of the time. I'm planning to get another gig as soon as I free up $100.
When you're talking about springing for more memory and desktop graphics power, that's really an area where businesses -- not consumers -- are likely to remain resistant. There's little reason for a business to outfit its accounting, marketing, and sales types with a graphics-heavy operating system, unless they're going to be lugging notebooks around to do fancy sales presentations.
On the consumer side, it's my feeling that much of the resistance to Vista, and the desire to stick with XP, comes from people who are comfortable with XP and see no compelling reason to change. That's how I felt, too, before I tried Vista. In addition, I thought I'd dislike Vista because of its heavy use of eye candy (its notorious Aero interface).
Well, Vista does use eye candy to a great extent. However, much as an attractive person need not be unintelligent, Vista's good looks don't mean it's not a good OS. It is, and I'm quite happy with it.
So, at this point I take Dell's Windows XP news to be more a statement of its desire to be responsive to consumers who want XP, rather than any sort of movement away from Vista. Indeed, when I went to Dell's Web site on Friday afternoon, the Inspiron E1405 notebooks, for which XP is supposed to soon be available as an option, were still showing Vista Home Basic or Premium as the operating system options. (Though when I clicked on the "question mark" next to the Inspiron OS selection, I got a pop-up flash screen promoting Windows XP Media Center Edition. Go figure.)
In short, Microsoft has nothing to fear from people who remain interested in XP. Rather, Redmond should perhaps start worrying about whether there's finally an opening here for open source. Linux on the desktop -- sure, we've heard that before, and it's never gone anywhere. But as they say on Wall Street, past performance is no indication of future results.