I didn't mean "typical" as in "most Rust fn signatures are like that", obviously most functions are far simpler. Who would even claim that?

I meant "you will only encounter this level of generics complexity in Rust" (disclaimer: I don't know C++). They can't be that rare either, I have not written a lot of Rust but already encountered similar constructs multiple times. But admittedly that might be partly due to no-std requirements.