I'm not sure why you think that the non-Chinese XP machines won't be potential customers. In my experience, the largest remaining IE8 (and even IE6) holdouts are big enterprises and government organizations. Those organizations are also some of the richest potential customers out there.
For our product (enterprise task and workflow management), we see about 2% IE6/7 and about 5% IE8 in our customer base. Of those customers, most are planning to upgrade away from XP sometime in the next year or two.
That's why I said often. If you specifically deal with a US govt agency or large corporate customer with a poorly run IT department, you may very well still need those customers. But for most consumer businesses, Windows XP users aren't really going to be customers.
For our product (enterprise task and workflow management), we see about 2% IE6/7 and about 5% IE8 in our customer base. Of those customers, most are planning to upgrade away from XP sometime in the next year or two.