No, I think you raise a good point about equipment, Footslogger. Equipment is one of the biggest reasons people don't take Fundies (at least that's what came out in the thread I started a while back asking why people who thought the class was a good idea weren't taking it.) And conformity of equipment is certainly one of the central tenets of the DIR philosophy.
It doesn't mean you can't ever dive safely with other equipment. There are tons of people who do. But even at the recreational level, there are advantages to standardizing equipment. I can glance over my buddies quickly and see if anything is out of place or twisted or improperly hooked up, because we all look the same. When I dive with somebody who doesn't dive the DIR configuration (or the NTEC configuration, depending on your particular allegiance), I have to spend a lot more time looking at what they have, where it is, and how it works. Underwater, it might take more time for me to help somebody with something, especially since I know I don't think as well at 60 feet as I do at the surface.
The gear configuration we use is simple, streamlined, flexible, and completely understood by all members of the team. But it's a big commitment to change, if you've started out with something else and you're happy with what you have. But DIR diving is a commitment, as RTodd observed in a prior post. For me, the returns more than outweigh the costs, but I can see how somebody might make a different decision.