Yes there is. You just aren't paying attention.
What does the PDGA have to do with state champions? I must have missed the dictionary entry that restricts state champions to ones that are recognized by the PDGA.
And, of course, none of this is really pertinent nor universal either. There are state championships and state champions. My state has been doing it for years.
The title of "Champion" only has meaning to those that recognize the championship. If your state has a championship, good for them. The winner probably takes a great deal of pride in the title, and people around your state may hold that person in some esteem, but outside that community of players, it's meaningless. That's why I mention the PDGA, that's the governing body that most of us recognize as the authority in the sport. If they formally sanctioned and recognized state champions, it would hold much more value.
If TimG decided to set up a DGCR members only tournament called The DGCR Championship that would officially crown a DGCR champion, would anyone outside of this site really care?
Except when it IS about identifying the best player specifically from a state/country.
There is—or at least used to be—at least one European national championship (Swiss, if memory serves) that awards/ed the title of national champion to the highest-finishing citizen/legal resident player, even if a non-citizen/non-resident wins the tournament. That is, anyone can compete for the event title, but only citizens/residents are eligible to win the championship title. (For an analogy, see the Braid Tailor Memorial Award, awarded at the British Open by the PGA of Great Britain & Ireland to the highest finishing PGA GB&I member born in, or with at least one parent born in, UK or Ireland.)
And, according Smigles, France and Germany restrict—or used to restrict—their championships to citizens/nationals.
That's fine if someone wants to create a state championship for only members of that state. But again, the title of Champion really only matters to those who actually consider that event a championship.