I believe the two main reasons are - inertia (don't rewrite something if it works; who really wants to own responsibility for testing this thing on all archite

I believe the two main reasons are - inertia (don't rewrite something if it works; who really wants to own responsibility for testing this thing on all architectures GRUB currently supports?) - multi-OS boot scenarios (I assume this new system will support that, but (a) I don't know for sure and (b) I don't really want to boot all the way into Linux just to throw Linux away and boot something else...)