PHP might not be that popular

Basically this is what I am observing.
Beginners in Web Development will most likely go for PHP. PHP is everywhere. Of course, they will likely be inspired by WP and want to make plugins and whatever.
But this is only the one side. On the other side, more advanced web developers are slowly moving away from PHP. JS seems to be very promising. It has inspired many very new technologies.
Let's take a quick tour.
First, there is JS. The kind of JS that will run in your browser making your homepage look aliove (animations, color fades, ...). This has been an important reason to learn JS for a very long time... yeah, maybe since forever.
But now, there also is Node.JS which allows you to also implement JS on the server side. It has a really good IO performance making it ideal for larger projects. Not only homepages, but all sorts of web servers with high IO (currently I am even thinking about making a game server partly on Node.)
Also there is this Javascript Object Notation thingy. Very many people prefer it for it's smaller overhead and faster/easier way of interpretation compared to XML. This was implemented in the NoSQL databases - which are also a completely new way to handle a great amount of data in an easy manner.
Beside these main arguments, there are countless other ideas why JS is in very many cases - mostly for homepages - a better choice than PHP or an other language.
As for the future, I don't think it will stop there. I hope, that we can also get rid of old HTML and CSS and welcome HTON (Hyper Text Object Notation) which would be some kind of JSON we could use to make homepages with.
To put it in a nutshell: why not use one language for everything?

Well, as for PHP, I don't think PHP will die out or be completely abandoned. It is an important language and if I have to do calculations it would certainly be a better choice than Node.
But I think, your statistics are only correct to a certain extend, since many developers who have been there for quite a while will rather move to JS than follow any PHP/WP hype.

As for PHP it is really very popular. According to Google, it is present in 75% of the sites. And that trend does not seem to slow down. Part of the reason is due to WordPress ever growing popularity. Even the cool kids that seem to embrace other technologies end up using WordPress because they prefer it.

Anyway that was explained already in this other article.

phpclasses.org/blog/post/215-7-Reas ...

As for JavaScript, and specifically Node.js, it could be a good idea but the intention to make it work asynchronously all the time make it a pain to program. In practice it would be a step backwards in productivity that many developers would not like to give.

Node.js is not new anymore, if it was set to replace PHP in terms of popular language, it should have already happened.

We commented about the eventuality of Node.js becoming at least as popular as PHP in the Lately in JavaScript podcast:

jsclasses.org/blog/post/3-Is-NodeJS ...

jsclasses.org/blog/post/14-Is-JavaS ...

And also in the PHP Classes site blog:

phpclasses.org/blog/post/133-Accele ...

phpclasses.org/blog/post/201-6-Reas ...

What's more efficient than install wordpress, customize and quickly deliver a beautifull and easy to use website to a happy client? Not every designer, blogger or web enthusiast want to be a deep coder. Web studios, web designers and non formal programmers made PHP strong. Wordpress is the most relevant piece of code of the entire internet! node.js, HTON, the end of html and css? Maybe tomorrow, who knows, but not today.

Yeah, that is exactly what I said. It is a very nice solution for people who don't know much about programming or just want to have a quick happy-with-one-packet solution.
If WP really is the most import.. I would not go that far (there are a lot of other very important languages out there with their own most important pieces od code... and it also depends strongly on what you want to do!). But it is definitely important for PHP as stated in this article.

I am rooting for tomorrong. Currently working on a project (for ~2y now) which will support a non-SGML environment (compatibilities still existant) with cross-language and cross-software capabilities.