For one, Linux isn't an RTOS and never will be. The many rejections of real-time patches into the Linux kernel tree have shown that the kernel devs favor perfor

For one, Linux isn't an RTOS and never will be. The many rejections of real-time patches into the Linux kernel tree have shown that the kernel devs favor performance to precision, so it would be a fool's errand to try once again to push a real-time patch just to get it patched. At which point, you'll end up having to do a lot of your own OS development anyways to backport kernel features you need. There are quite a few situations where Linux will delay interrupts for milliseconds, and quite a few situations where milliseconds can mean millions of dollars. For your last question, 20 years of support will certainly not Linux developers. While MS offers extended support for Windows XP, neither earth nor the heavens will make Red Hat provide extended support for RHEL 3. The Open Source world has a lot to learn from proprietary companies about support still.