I believe it was actually SP1 that included the SATA drivers with the OS. The original release of XP doesn't have SATA drivers included, that is correct.
Hardly anyone has the original release anyways so I don't see it as a problem really.
So how do you bypass it if you're reinstalling windows on a SATA drive?
Well most (if not all) Windows copies already come with at least SP1.
So it's a for sure thing that SP1 has the SATA Drivers?