As a developer, I'm always reevaluating what tools I use to do my work. This can be what language I'm using, but also what frameworks, libraries or editors I'm using.
If you look up PHP on Google Trends it doesn't look pretty. It's "web search interest" has steadily decreased since 2004 (the earliest data you get in Google Trends). However I think this is a red herring. PHP is such an elephpant in the room (har har) that it's not enough to be a PHP developer these days, you have to specialize. We have WordPress, Yii, CodeIgniter, Symfony, Drupal and about a million other frameworks and applications that are built in PHP, each have become ecosystems of their own.