Couldn't you just boot the Linux kernel directly and launch a generic app as pid 1 instead of a full blown init system with a bunch of daemons?
That's basically what you're getting with Docker containers and a shared kernel. AWS Lambda is doing something similar with dedicated kernels with Firecracker VMs
Yes, but I wanted to bypass having the complexity of the Linux kernel completely, too.
Basically single app directly to network (the world) and as little as possible else in between.
Yes, you can. You can even have a different Pid 1 configure whatever and then replace it's core image with the new Pid 1.