Both my current and previous day jobs involve building an edge network, which involves doing TLS termination: that means dealing with a lot of crap that comes y

Both my current and previous day jobs involve building an edge network, which involves doing TLS termination: that means dealing with a lot of crap that comes your way - much more traffic than is valid/legitimate traffic, because on the public internet, anything goes. So I may be biased here. The situation for a purely backend service (behind an existing reverse proxy) might very well be different — but as others have mentioned, the Rust http ecosystem has solidified around async, so even if you could get away with 1 connection = 1 thread, you might not want to, just because of where the ecosystem is. One thing I didn't mention is that epoll isn't even state of the art: there's a lot of work going on around io-uring and thread-per-core runtimes nowadays, which I'm following rather closely because again, at my day job it does matter!