Tock is probably closer to a true RTOS in the sense that tasks have stacks. Maybe also hubris. RTIC, embassy, and probably a few others do ISR preemptive task scheduling and synchronization. This is super cool and probably enough for most people. Until you need time slicing probably. Threads have pros and cons like anything else, the biggest cons tend to be…

Stack sizing is hard. Stack swapping kills caches. Stack overflows can be very infrequent and hard to debug. Thread priority doesnt always do what you think. Even with threads not every RTOS does time slicing.

So right is there a complete network/usb/ble stack in rust today? Not that I’ve seen. So I can understand needing those and thinking maybe it’s not quite there. I do think though that some really interesting and cool ideas on scheduling, device Hal’s, and state machinery has been pretty well explored at this point. It’s still young but evolving and maturing quickly.