For the simple reason that Empire sucked. And I've got better reason than most here to complain, since I seem to be the only one who spent money on the DVD. We'd never heard of the sereies, and thought it might be a European show that just hadn't made it to the US market.
We're well-known at our local FYE, so were able to trade it in on a used Looney Toons boxed set.
I spent money on it as well, unfortunately. It was entertaining, but in terms of historical accuracy, I'd give it a 1 - and that's just because they were adept enough to at least get the names spelled right in the credits.