I've tried Golang and played around with Node. They're fast, sure. The respective frameworks just don't compare.
Ruby (and Rails) scales just fine for 99.281% of things. You just need to throw money at it.
And that's a great thing.
A business's success will never depend on of the speed of a language or framework. It just doesn't work like that. What matters is how quickly you're able to iterate and evolve a product.
Ruby (and Rails' ecosystem) allows me to not have to reinvent the wheel for mostly everything. Authentication? Devise. ORM? ActiveRecord. Background processing? ActiveJob. Caching? It's there.
Want awesome front-end performance without having to basically rewrite your entire app and learn another framework and manage its dependencies? Turbolinks, and it has matured beautifully.
Basecamp has its performance anecdotes written in history that we can all reference. And Basecamp also has had great success.
Point being is that a business is a business. The speed of a product cannot and should not be blamed for how successful a business is or isn't.
I love you, DH2, and thank you Matz. I love you too.