Charging full price has nothing to do with managing costs. Whether pre-pandemic or during a pandemic, businesses always want to manage their costs/expenses.
Just because they're not charging less doesn't mean they aren't looking to reduce their costs.
And, yes, from a customer's perspective, it is galling to pay the same price for reduced goods and services.
However, from the parks' point of view, they can't cram in all the customers they'd like who, in total, contribute toward fixed expenses like keeping the lights on and cleaning and maintenance and depreciation. So, they have less customers covering those costs, which means they can't deeply discount the cost to the much fewer guests that are there.
Think of it this way, if there was just one guest that showed up on a particular day, how much would they have to pay to cover the costs of opening the park for that day?
