Because it's deployed on nearly every web server and has ubiquity. If you're building a web app and you want people to be able to run, chances are good if you build it in PHP, people can run it. Would be nice to say the same thing about server-side JS.

Because nobody wants to be the next Rails.

I think I'm lost on the joke; nobody wants to be the next overhyped (and polarizing) framework that is beloved by a large niche of programmers and launches a new segment of the industry?

Care to clue me in? (being honest; maybe I missed some news recently)

php sucks

I think he means Ubiquity when he refers PHP. Not necessarily technical.

because it is a cinch for sysadmins like me to support in a bureaucratic IT environment