ThreadX is just the scheduler / OS functionality. There are tons of other components in the firmware (namely, the parts that actually do things) which are still

ThreadX is just the scheduler / OS functionality. There are tons of other components in the firmware (namely, the parts that actually do things) which are still encumbered by patent and copyright issues, not to mention the DRM modules which are somewhat security-by-obscurity based. It's one step closer to an open Pi firmware in some ways, but probably not a meaningful step.