That's the entire rationale behind e.g. using python or php on the backend. Oh, the requests are IO-bound, we don't need to use a cumbersome language like C++ or Java to develop our backend, we'll just throw more cores at it if it gets too slow. Developer time will always be the first thing to be optimised, not least because the first to ship win and the first to ship is the one with the fastest development stack.
