BeOS died because Jobs torpedoed their negotiations with Apple with his return from NeXT. Prior to that, the odds were good that BeOS would become the next OS for Macs.
Apple was the last-chance for BeOS. They were actually gaining ground with PC channels, until Microsoft declared that anyone selling a non-pure-windows system (including dual boots that default to windows) will lose their discount on the Windows OEM license.
Guess how many PCs were sold with BeOS after that happened? At that point, it was Apple or bust. And then it was bust.
