I've found the idea of unikernels interesting for several years now, is there a tl;dr on why they don't seem to have taken off, like at all? Or is it all happening behind some doors I don't have access to?
I think that part of it is that relatively few people use bare-metal servers these days, and nested virtualisation isn't universally supported. I also found this technical critique [0] compelling, but I have no idea if any of it is accurate or not.
The majority of nanos users don't do either of these methods. They simply create the image (in the case of aws that's an ami) and boot it. This is part of what makes them vastly more simple than using normal linux vms or containers as you don't have to manage the "orchestration".