HN user
Al Jazzera has a great exposé on the issues of quality and supply / demand for pilots in Asia. https://www.youtube.com/watch?v=qSZ-R5HdPQU
It's truly frightening, and makes me think twice when any of these airlines come up when I'm searching for flight deals.
Quite simply, it's great market fit.
JavaScript has extremely low barrier to entry. Everyone has a browser, so you can get someone to get started without download any software. That's huge.
Rails has the benefit of providing a framework that can get someone building functional CRUD apps in a tremendously short period of time.
Between those two, you've hit a nice sweet spot where someone can be fully functional as a developer in a short period of time (talent/quality/patience aside).
During the early 90's we used to reverse-engineer computer viruses (DOS) at the Peter Norton group using SoftICE. All in the name of creating repro's and fixes of course.