To be fair, much of the needed work was accomplished in the Dan0 development release that was leaked near BeOS's demise. This included the BONE network stack and some 3D support. Everything about Dan0 was, of course, very much development code, but it was definitely a marked improvement over R5. Haiku was able to use some of the Dan0 high level kits in place until rewrites could be made.

Clearly the Apple/Be Inc. issues were sorted out to Apple's benefit, but it's still neat to see what could have been. OS X had its own issues in its widely released beta, after all. ;)