JS is on the rise, but no one hires anyone to write just JS. It's usually JS and PHP (and of course, HTML, CSS).
And another point, outside the bubble (I mean a place like Florida) it's hella easier finding a decent PHP guy than Python (or Ruby) guy. I learned that the hard way.
The job market in CA is very different to pretty much everywhere else in that emerging and niche technologies tend to be under-represented outside of CA, most likely because of budget constraints in web development, most clients want a simple Joomla or WordPress site and couldn't care less about anything else as long as they don't have to pay over £2,000 for it.
I've never received offers for anything else.
You are joking. Right?
There are many good job opportunities for JS developers. I don't know where you got the idea otherwise.
FWIW, I was hired to do just JS.
This is false. It is very easy to make sane URLs in PHP. You just designate index.php (or whatever you want, actually) as the default index in your http server. In fact, that's how it works in every language?
They don't say how they determine whether a technology is being used server side -- it could be only if they see ".php" URLs on the site, for example, which would mean there would be a strong bias against languages that make it easy to write sane URLs.
They also don't share what % of sites they're able to make a determination for at all, so these numbers could be based on a statistically insignificant sample.