While consulting I had several clients in the top 10k websites using Rails making millions and millions of dollars a year.

So, I guess I just fundamentally disagree on the 'big' portion of that statement, but also, I think apps are by their nature not long lived, so I think it is a false requirement of a web framework.

That said, I also have had work I've done in Rails still powering the same website almost 10 years on, cacm.acm.org