Six months in advance the only place in the park she could find the rooms was at Grant Village, one of the less attractive locations. That tells me the economy isn't doing too badly. Many people feel sufficiently secure in their economic status to have already made their summer travel reservations.
To be sure, perhaps as many as 20% of Americans are in some kind of economic bind. We tend to forget that the glass is 80% full, most Americans are living more-or-less as well as they did five years ago.
For that 80% their house is worth less, but they've gotten over that downward swoop. It appears they have enough money to buy high priced gasoline to drive the family car to northwestern Wyoming to see the critters and the geysers. Plenty of them don't plan to stay in a tent either.
Yellowstone is beautiful, they'll get their money's worth.