If you read archived planning board documents on the Queensbury Town Board website, they go pretty in-depth into what the different traffic level thresholds are, and what the "consequences" are for hitting them. In addition to what you mentioned above, another "consequence" that was mentioned in those documents is that Exit 20 of the Northway would potentially need to be extended/expanded to handle an increased car count. I don't remember if GE would have to contribute to that cost, but it's still an undertaking (and, well, this is the US where we only touch roads when they're literally causing harm to vehicles/people).
If I'm ever bored enough to search through the documents again, I'll link them (not that anyone actually cares). But lets be real, if the park can get away with charging $20+ to park, $15 for chicken tenders & fries, etc. and still maintain a decent attendance level with inexpensive additions, then more power to them.