So, by lumping together four (or five) different platforms, you manage to come up with a number that is larger than those using Rails? That's not entirely surprising.
You're also counting Javascript, which I find odd. Javascript is used in ALL of those platforms, so including it in an argument is extremely unfair. I do some Javascript programming from time to time, but I also spend a fair amount of time in Rails. When I was doing PHP and ASP.net programming, we were also using Javascript. So, yeah, there are going to be more jobs for front-end developers than those who program in some back-end platform, because all sites need some sort of a front-end (excluding some project that's purely an API).
There's also a dilution of programming jobs for the aforementioned platforms, from my experience. Finding a job doing Rails seems to be fairly easy as, even though it was the "next big thing", the average programmer felt better sticking with Java, PHP, or ASP.net. There are way more Java programmers than there are Rails programmers, but it seems the ratio of programmers to programming jobs seems to be more in the favor of Rails.