[flohofwoe]

This would probably have meant that the Mac wouldn't have become so popular amongst developers. At least that was the reason for me to switch to Mac because it's a "proper" UNIX with a window system that actually works ("Linux on the desktop" has mostly caught up in the meantime, but 10 years ago that was quite different).

[yjftsjthsd-h]

Haiku has a perfectly good POSIX layer; I expect it would have been fine.

[rvense]

BeOS was less compatible. There were also many improvements to it in the later versions. When NeXT bought Apple[0], BeOS was not even in its pre-release phase. Its heyday, such as it were, was really on Intel, with R5 and the Personal Edition, in the last few years of the 90's.

[0] For -$400M :)