Well if you're a Python person, Django is amazing, and if you're a golang person Gin Gonic is amazing. Not everything webapp is Rails, although Rails is wonderful for prototypes. The only two very large rails sites I was ever consciously aware of were Twitter (now all java) and Groupon (now mostly node).
Kickstarter, AirBnB, Github, Scribd, Bleacher Report, Hulu, Codeacademy, the 100+ startups that message me for interviewers every year, etc.
I was only making claims for rapid prototyping. I still contend for prototyping there is no better framework than Rails. From the start DHH designed Rails specifically for prototyping of web apps, and your custom prototyping infrastructure will sit very nicely on top.
