I've been around for quite a while. While it's certainly true you can find employment by saying "I can use tool X quite well", (although it will depend on X, and whatever is considered "hot" in the current era), you are limiting yourself.

It's easier to get someone to learn a new language then it is to turn a web-programmer into a systems programmer, or an applications programmer into a system administrator.

If I hire, or am involved in the hiring process, the languages you know can certainly play a role - but I'm far more interested whether someone is a network person, an application programmer or something else. Certainly, if the hiring is to fill three floors of programmers to write a gigantic financial application, it's generally known what language they'll be coding in. But that usually isn't Perl. It used to be mostly C and C++, and Pascal before that. Currently, it's more Java and .NET. Perl is a lot more used in jobs where the job description requires you to do certain tasks - with much more freedom to use tools.

Remember that more people are hired to be a carpenter, than to be a hammer wielder.