I always liked the BeOS interface—at least, in the context of the early 90s, when its popularity peaked—but I find it pointless to clone a 20+ year-old UI. With Kinect, Leap Motion, and other forms of input, it seems like there's a huge opportunity to get away from the traditional windowed UI that has dominated desktop OSes.
Not to knock Haiku OS—I just feel that if someone is going to create a desktop OS from scratch, it's a chance to do something really different. I see this as a missed opportunity.
It's not the UI that excited technologists enough to recreate it from scratch. It was the design of the operating system and its API.
BeOS was state-of-the-art when it was written, in the sense that it took the accumulated wisdom and academic research up to that point as its starting point. And in many ways it is still state-of-the-art.
I do not know BeOS that well, but I disagree with that "accumulated wisdom and academic research up to that point" claim. The prime reason is this: http://2f.ru/holy-wars/fbc.html. Although that probably helped performance-wise, I see that as a gross hack, not as a thing to follow. If BeOS had lived on, I think that decision would eventually have haunted them.
I also remember that, in its time, BeOS was innovating quite a bit in its pervasive multi-threading ('a thread for each window').
Or were both based on research papers or older systems? If so, I would like to know which these were.
When OS X came out (both the Mac OS X Server 1.0 and Mac OS X 10.0 varieties), the UI might have looked different, but you were basically running OPENSTEP 5 with a new coat of paint. Haiku could do a new theme fairly easily at this point, and there are already quite a few touch-ups of the new-slab-of-paint variety (e.g., subpixel antialiasing, support for tiled windows, various improvements to OpenTracker).
The other thing that OS X brought to the table were new APIs, but most of these APIs weren't really user-visible per se. (E.g., QuickTime was a genuinely new addition to OPENSTEP, but the end-user would just see it as more videos played now, and they played with lower CPU usage.) Here, too, Haiku has delivered: it has new APIs for component layout, new APIs for end-user notifications, and more.
So your comparison to what Apple did with OS X is actually quite apropos. Be just hasn't felt a need to overhaul the UI as radically as Apple did in going from OPENSTEP to OS X--in large part because, while some of those changes were functional, many of them were more about making a statement than being genuinely easier-to-use. (Note how much OS X 10.6 and 10.7 have largely reverted to a kind of brushed-up version of the old Platinum interface: no more pinstripes, flat grey buttons in most cases, flat grey title bars, etc.) So I think they're doing exactly what they ought to be doing.
It's entirely time and money. They only have so many devs, most of whom have day jobs, and pretty limited funding to support them, so the UI (and many other polish-and-details things) had to take a back seat to more important core functionality.
Because it is extremely much work, both in the research/prototyping/design and in the implementation. And when you are done, there are no apps that supports it.
I assume they don't exacly have a huge community of active devs. combine that with the fact that user interface design is hard and needs experienced people working on it and you got the reason for cloning a perfectly functional UI instead of completely messing up while innovating a revolutionary new one.
They didn't set out to create something new and wonderful, they wanted the operating system that they loved to have a life after Be. Recreating that OS was a design goal, because if they had decided to create something new and different then they would have had to sit down and figure out what exactly that means and nothing would have ever gotten done.
Haiku has always been about recreating R5, just a bit more modern, because it's a goal everyone can agree on and no major design work was necessary.
(An even older one, as it happens! But even that is arguable; change the shell, the terms under which it operates, or even just the available commands, and that's a UI change.)
True, but the UI elements traditionally associated with BeOS came out in ~1996—so I stand corrected, it was a few years later than I stated in my original comment.
Not to knock Haiku OS—I just feel that if someone is going to create a desktop OS from scratch, it's a chance to do something really different. I see this as a missed opportunity.