Years ago, you had to suffer using poll(), select(), whilst dealing with threads or forking. It's so easy these days. A raspberry pi should be able to support 1,000 clients with any of the above recommended languages.
The original article is condescending to say the least, that doesn't mean that $4k of ongoing hosting costs shouldn't be able to handle a few million simultaneous users... though, something tells me that Pokemon Go could approach twitter or FB overhead, and related apps like chat could see huge swarms as a side effect.
That kind of problem would kill most first generation apps, as those who've seen twitter grow can attest to. I don't think there are any IRC networks that big at this point.
If you have problems with this, there's something really wrong with either your design or your choice of tools.
How'd you go about building this?
Now I would use pusher but that's extremely expensive but scalable.