I work at a company that does ruby “at scale” too (10mil b2c users). Yes we need more web instances than we would have in go(or whatever). No, it doesn’t really matter at all - web process compute is a tiny fraction of our AWS bill, and a meaninglessly tiny % of overall op-ex. We’re talking sub sub 1%. It doesn’t matter, really.

Of course if we had a few billion users , diff story, but approximately no one does.