I wonder what would make this better (for some use cases at least) than venerable FreeRTOS? Or Zephyr? Or any of the other many, many RTOSes? In particular, the ESP32 comes with top notch documentation and SDKs that will make beginners at least want to stay with Espressif's modified RTOS for a while.
That's also what I was wondering. What problems is this custom RTOS solving that all the other ones don't, or is it in fact just that some Roku engineers decided they needed some job security and having an OS nobody else uses would be a good path to that?