I'd find it difficult if all I knew how to do was code php and I wanted to create a brand new community with game servers and forums or if I wanted to create an interactive web application.

There is a lot that could go into it. Frameworks, Admin tools, operating systems, other languages etc etc.

Focusing directly, 100% on a language isn't necessarily the best choice. It is important to make sure you understand how the language works, but there is more to it than that.