I don't think that it is a problem is Jr Perl developers. It is that they don't want to pay much for a programmer. If there is not a problem finding good, experienced Perl developers then it is a question of money. They just don't to pay $30-50/hour for an experienced programmer, they want to pay $15-20/hour.

Also, there are just marketing cycles where companies will pay absurd amounts of money for a programmer for the latest technology. For example, this fall, recruiters were desperately looking for .NET programmers for $40/hour of 2 or 3 years experience. Java programmers, they did not even call them back regardless of experience becuase they were viewed as a dime a dozen...

The fact of the matter is, companies, especially large companies are just crazy, sometimes they will overpay for a technical skill and other times will pinch pennies for another.

The reason for this is that companies, especially large ones, just don't know how to measure productivity. So they go with the only concrete thing they can grasp, experience with a particular technology and hope that the next technological product they are investing in will increase productivity.