Yes but the point is that lots of people became disenchanted with ruby because it was notably harder to get this sort of thing right than it was for the alternatives with more built in support for in-process concurrency. Maybe it's not the case anymore, but back around 2010, the only people who knew what they needed to do to configure a rails app to scale decently were those who had battle scars of the kind in the parent comment. And nobody came out of those battles feeling all sunshine-and-roses about the platform.