It's a CRUD staple. There's no other language so well suited to easily building CRUD services (of which WordPress is one). It's a big cherry on top that the language has gotten better and dramatically faster over the last several years.

There was no chance of it being killed off rapidly as the author was perhaps implying. It might have slowly rotted away, had the maintainers not stepped up with v7 and hit a home run.

PHP powers a couple of the software packages used by over 50% of websites. Mainly being Wordpress. Impossible to know but I would guess that new development of PHP sites is not such an impressive stat.

PHP runs the long tail of the internet. And somewhat accidentally, it also runs Facebook :-D