When you're trying to ferry boatloads of bits down the information superhighway, the Mack truck starts to look pretty good. Sure, the automatic transmission Mustang is cheap, quick to acquire, and easy to find drivers for, but you have to get 10 of them for every Mack truck's worth.

Given that FB's solution to their PHP problem was to discover the static typing, I'd say that PHP is not the proper tool for the current job.