I live in the Denver area, but I can, if I choose, make it round trip to the lake and back without needing to stop. I'd still get fuel in my local station. I use no more food/groceries than when I am at home. And I can bring enough fuel to never need the marina. And the ANS/AIS program at Powell really holds no value for me as I have to be decontaminated in Colorado regardless of a Utah inspection.
Plus all the reasons that Squirrel said.
Bottom line, it should be open to everyone or no one. And I am of the opinion it should be open to everyone, all the time.