There's a difference between using a brand-new Node.JS framework that's barely out of alpha and using Rails/Django/etc which whilst fairly new are proven to be stable and reliable, and are in use at big organisations.
I agree, however there is no defining line for the non-tech savvy that determines what is bleeding edge, and what isn't. Is Ruby going to be around in 5 years? If Ruby is around, will I be able to hire developers easily and for a reasonable price? These are concerns that drive businesses for whom tech is a necessity but not the core of their business.
So the business owner relies on the tech provider who hopefully isn't in a full on romance with the newest framework/language just because it's new.
Ruby (the language) and rails (the web-framework) are not the latest fads to come out. Rails hit 1.0 in 2005, a.k.a. almost 8 years ago, ruby is much older.
Although there can be good reasons to choose something new, I agree with your overall sentiment. But we seem to have extremely different views on what constitutes "new"(node might qualify :)
I wasn't specifically using Ruby as an example of new/unstable tech. My point was that your average business owner doesn't know Ruby from ASP from Perl. It becomes the job of the tech provider to implement technology that not only serves the need now, but also the need years down the road.
So the business owner relies on the tech provider who hopefully isn't in a full on romance with the newest framework/language just because it's new.