I can't speculate about the Big Sur question, but I'll take a bite on the other one
Two reasons I suspect –
Firstly, while incredibly neat, and I keep trying to talk myself out of getting one every 3 months, the GDC beast is a very niche piece of kit. Only a very specific class of enthusiast, who happens to want to game on a laptop with no discrete video card or thunderbolt, and in 2 of 3 different ways to install the GDC, is happy to either leave the mini pcie or m.2 bay wide open (or use an expresscard, but $deity, Its been eons since I have seen one). Essentially the people best suited to try to find a problem are pretty rare on the ground anywhere.
I'd also say it's December, and folks tend to be less active around then.