"so your idea still raises the cost of the overall visit." - Sure as everywhere else under the sun, the System needs restructuring due to $$$ being spent unwisely, but people are entering and accessing Parks without paying. How wise is it to let a vehicle enter with 15 people in it and only charge, at the current rate, $25 for ONLY 15 people??!!
If you are local then you should be buying the annual pass! I access the ONP with irregularity, sometimes twice a year, sometimes a dozen, but regardless of how many times I get the annual pass. It evens out and it is the right thing for me to do. If I go once and the Park makes money off of me then great!...if I reap the rewards through my pocketbook because I went 10 times, then good too. If I am accessing ONP from a secluded or unmanned station, I'm covered because I've done the right thing in the first place. I do exactly the same when I go to Rainier.