Typical case of looking only at the American market.
HSPA is nothing new in Europe, we've been having phones supporting it for several years. It's hardly the big selling point in other markets as it seems to be in the USA. People aren't not buying the iPhone because it doesn't support HSPA, the 3.6 Mbps offered on 3G seems to be keeping people content enough.
On the issue of 4G and HSPA, can we please just settle on the fact that HSPA is simply "3.5G" and nothing more. I don't see why people are getting worked up about the next iPhone needing 4G, LTE or whatever either, 3rd Generation tech has been around for over a decade (my Dad works in standards and was involved with 3G and now LTE) but it's only been in the past 3-4 years that the benefits of 3G tech have really taken off. It's for this reason that I can't see any benefit in being the first out with 4G technology; there's simply no real demand for it.