When you said "Is there a point to poly without [variety]?" I felt an urge to respond.
I'm not poly to have variety, although I certainly am getting it. I'm poly because I want to have the kind of relationship with each person in my life that makes the most sense for who we are together.
That happens to mean that there are two people in my life who are both my life partners-- we live together, share expenses, and are making plans to buy a home and have children. It also means that I have several friends who are more than friends romantically or sexually or both, because that's how it makes sense for us to be together.
While I'm already chiming in, I'll echo points made by Lemondrop and CielDuMatin... If your DPG is what you want to do with the people who enter your life, great! I wish you the best of luck in implementing a system that works for you! If you're hoping that DPG will become some sort of large, over-arching system to encompass many many poly individuals, then you're still welcome to attempt it, but my two cents are that it doesn't feel workable for myself or my partners, and so we're not interested. Thanks anyway!
I'd also like to add that something in your language, jackrabbit, has been picking at me, and I just figured out what it is. Your use of the word "fall" when describing how many poly people enter relationships... it just feels accidental. 'Whoops, I wound up here! Better dust off and keep going...'
While many people do discover the idea of polyamory by winding up interested in two people, or winding up interested in someone who identifies as poly, it still takes a LOT of work to be in a poly relationship, and is very much a conscious choice in a lot of cases. For my part, my Barbie dolls lived in a polyfidelitous tribe (as nudists, no less) when I was a little girl-- poly has always been part of who I am.