Every hardware manufacturer has to supply drivers that will run on any PC, any BIOS, with patches to make his hardware work on all versions of Windows. His hardware is expensive to make and has to be made as cheap as possible. There will always be some incompatibilities between what he has designed and someone's particular hardware or software setup. Fix it in software - you only have to pay once for that.
When a manufacturer finds that his new hardware doesn't do this or that under these conditions, he patches his driver software to make it happen (which is why new Windows drivers are issued so frequently). He calls it an upgrade, his competitors call it a festering bug. The result is the same, his hardware now works under more conditions than it did last week.
VIA can't afford to make their chipset work under all conditions, and the others can't, either. That's why every piece of hardware comes with a "Windows Install CD", which contains drivers and patches for the OS.
Mai is no different. At this stage of the game, there is only one (available) chipset that supports AGP for PPC, and that is Articia.
Consequently, everyone that wants to use Articia for hardware access has to make their drivers do the interfacing in software. At the moment, no hardware manufacturers are releasing video cards or anything else, tailored for PPC boards or particular PPC OSes. So the OS developers (Hyperion, Genesi, the owners of early G3/G4 boards, Mai engineers) are having to do the software work.
It's not a big deal, it just takes time.
tony