There's no question that the best employees are the ones that are actually interested in their job and enjoy learning as much as possible. They'll understand new technology faster, pay more attention to perfecting their projects, help out other employees, and contribute to a better work environment.

I think negative situations like the one you described occur because of two main reasons:

1. The company hires people based on just credentials and doesn't look close enough to see if they're really interested in the given field. It is of course hard to measure this sort of thing, but can be done (involvement in a community like perl monks is a dead giveaway ;-)
2. The work environment is boring and doesn't encourage any innovation. For example, if your supervisor criticizes you for writing a (perl) script to do a simple task, claiming it's inefficient.

Rather than hire the person with the most pieces of paper, it is far better to hire people who are easy to work with and enjoy the job, even if you have to spend some extra time/money training them.

Just my 2 cents

/me waits for some of those rare phd. downvotes :p