What car do you use to go to the supermarket? An F1 car? A truck? A sedan? JavaScript is totally fine for serving thousands of reqs per second. In many cases t

What car do you use to go to the supermarket? An F1 car? A truck? A sedan? JavaScript is totally fine for serving thousands of reqs per second. In many cases the bottleneck will be third party APIs or the DB. The cost of running that will be negligible. If you have hundreds of thousands (or millions) of reqs per second, then of course cost can become an important factor. But at that stage you probably have the resources to build whatever you want with the best possible language for the use case.