I think the problem was the same as that faced by languages like D competing with C++11: It wasn't "better enough" than the alternatives. It was better than N

I think the problem was the same as that faced by languages like D competing with C++11: It wasn't "better enough" than the alternatives. It was better than NeXT (what would become OSX), but not enough to be revolutionary. It was better than Windows, Mac Classic, and Linux, but also not enough to be revolutionary. The existing closed incumbents won out by market share and inertia, and Linux won out by being free, open, and by basically going viral. If BeOS had been open and free I think it would have given Linux a run for its money, but it wasn't.