I was using Ruby before Rails existed, when it was just a "really cool new OO language." At this point I'm done with Ruby because of its many, many problems, and I'm truly amazed that Rails is still as popular as it is. Ruby has gotten so crufty that you need Ruby install managers to track and maintain your various Ruby versions and their respective install libraries. It's a nightmare.

Node.JS is cool in concept; in practice, the code ends up being really ugly because JavaScript doesn't have real closures. Callback hell. You know what I'm talking about.

I'm using Ngnix+LuaJit to get even more performance out of the same server hardware than Node.JS can provide, and I don't need to have nests of callbacks to get non-blocking logic since Lua supports true closures. The code is positively readable, especially compared to Node.

My only regret is that some of the cooler JS client libraries (socket.io in particular) require Node.JS on the server; for my current project (which involves HTML5+JavaScript+networking) it would be really nice to have, though I've already got the Nginx+LuaJit(+ZeroMQ) part of the architecture working, so I'm loathe to add a Node.JS server in addition just to avoid long polling.

So no, you're right, if I were to work with a startup that needed high performance servers, I'd probably not want to be tied down to Node.JS or Ruby. If someone wanted to hire me to handle that problem for them, I wouldn't need the "youngsters" to help me out. But I have enough gig options that I can say no to ones that I don't like. :)

And before you say that "no one knows that stack!", code written this way is far easier to understand by anyone who knows any stack, and that means it wouldn't be hard for a Node.JS expert to step in and maintain it. There also exists a thriving Lua community to pull developers from, for that matter -- some of whom maintain the stack I use. [1]

[1] http://openresty.org/