What is the most exclusively military auto insurer, now?

Now, you can be a USAA member if you are a step child of an ex-husband of a service-member's daughter. You can read about that here:
With USAA expanding their memberships to anyone who can say the word "military," I'm beginning to wonder if there are any exclusively military insurance companies out there. Presumably, military members would be a lower risk category and would have lower premiums. It stands to reason then, that as USAA expands their memberships, the lower risk among us pay higher premiums than we would if another company catered exclusively to us and did not need us to cover higher risk individuals. So, I'd like to know if there are any other companies out there with more military exclusivity, or if there's enough of an interest in creating a new insurance company. After all, USAA was originally created for and by military officers. It worked out well once, and it may be time to start that process over again.