Not trying to recreate the mess we had up there a few years ago, but, sticker sales are important, lack of sales to those in charge = lack of interest.
A clear example of this, in my town, this year, they saw a drop in the # of permits for Nauset Beach, and a drop the year prior... they are already factoring running the town without the revenue from the sticker sales, diminishing it to 0 income
, projected out over the next 3-5 fiscal years, and some of the bean counters that run this town, are already saying what a savings it would be to the town to not have it, personel, (pay and bennies etc.) equipment, ( depreciation and maintenence etc.), etc. ... they even talk of it like it would be a Good Thing!.. I am sure the Park Service bean counters would look at a diminished sticker income the same way.
Buying a sticker, while it doesn't have the same bang for the buck it once did, is still a way, of telling those in charge, to Keep It Open!