If you asked this question in 2011, the reply would have been: “probably yes, but only because of the massively huge code base developed in 15 years”.
In 2017, we have to reply: “There has been a disruptive factor called PHP 7. It changed a lot in the backend development perspective”.
PHP 5.5+ had been a big step up already. From the ancient, C flavoured spaghetti code, to a proper rich and modern language. PHP 7 is not “just” monstruosly fast (it’s been reenginered from scratch), it also takes a LOT of the “good stuff” from Java and other good languages and makes it extremely easy to create proper code. Code fast, code fast code (!) and have nothing special to install. No stale compiled files, no need for complicated sources building software, no need for a compiler at all.
PHP is still very relevant! Since the release of PHP 7, the language is now being concidered as an enterprise programming language. This means that it’s used a lot of places where big work-loads happen.
The true magic with PHP is that there are different frameworks that makes your code very nice to look at; while also making your job very much easier. (little plug for Laravel ;))
Yes it still is and it will be for a long time. At least in web development.
WordPress is powering close to 75 million website and that uses PHP. I work for an agency that is trying to get PHP developer for 12 month and is still employing. In the UK is a large amount of open PHP jobs and I get contacted at least once every week from companies offering PHP jobs.
If you want to get paid for your work and want to be able to choose the company you work for then PHP is the language you need to be good at.
It is just shifting away from being the only major server-side scripting language to one of many, that is all.
It is true that it became out of favor for high volume sites and large-scale commercial infrastructures lately but it still remains really popular for small to mederate sized applications.
If Facebook was about to be developed today, probably it would not be developed in PHP, but that does not make the language irrelevant at all.