"Venture a guess why this might be?"
In my experience many translators have fairly low self-confidence and are not that keen to approach direct clients. Oddly enough, they do seem to be prepared to put up with the crap the less competent agencies (such as the one referred to here) throw at them. Fortunately there are now support networks and books such as "The Entrepreneurial Linguist" to help translators develop their businesses more effectively. Incidentally, it's not only a matter of being able to charge higher rates, but also making the work more enjoyable by getting more involved with the subject and receiving more feedback from the client.
(Note: I'm not against agencies per se, some of them do a good job, especially on projects involving a number of languages and subjects. So I'm happy to do the occasional subcontract job for folks like that - unfortunately I get the impression they're the exception.)
Biting the hand that feeds IT
