The reason I posted the idea was to start with a system that is working and where you can forego the filesystem and other parts that are typically found on a full blown OS. It's not uncommon for an RTOS to dismiss the GC and leave it to the programmer.

For example, there are discussions in the RTOS world to take a closer look at Rust (Google embedded Rust) which is why the terms "new OS", "GC" and "experimental" triggered my response to look over there for a starting point.