See TamaGo, used to write firmware in Go, being shipped in production.

Not familiar with it, but reading the github page it isn't clear how it deals with GC. Do you happen to know?

Some embedded use cases would be fine with a GC (MicroPython is also a thing after all). Some want deterministic deallocation. Some want no dynamic allocator at all. From what I have seen, far more products are in the latter two categories. While many hobby projects fall into the first two categories. That is of course a broad generalization, but there is sole truth to it.

Many products want to avoid allocation entirely either because of the realtime properties, or because they are cost sensitive and it is worth spending a little bit extra dev effort to be able to save an Euro or two and use a cheaper microcontroller where the allocator overhead won't fit (either the code in flash, or just the bookkeeping in RAM).