I guess the question is what does that have to do with it? Why not just work asynchronusly with requests that hit the server with a library like lparallel with their futures? Isn't it about the response to the request?
High level, yes. Mid/low-level, it really depends on what you're doing. If you're serving static files, sure, use Nginx/Woo. If you're running an evented CL application that deals mostly with network i/o, threading is going to be a tank when you need a hummingbird.
I built cl-async/wookie as parallels for nodejs/express in common lisp.
If so, I agree a lot with what you said!