I'm sure I'll be able to hear a collective gasp of horror from this, but I just don't think the prices at Kings Island are out of line at all. Even when compared to the cheapest fast food restaurants, I don't think their food prices are out of line-and yes, I find the quality to be normally as good as if I had ordered it in just about any other restaurant. I find their souvenirs (shirts, hats, mugs) to be in line with anywhere else you find that stuff. Prices are higher everywhere you go (and will continue to do so). Amusement parks definitely aren't going to be any different.
On a typical trip, I normally buy pizza. I think it's what, $6 for two slices? But, my goodness, look at where I'm at when I'm buying it...a beautiful park filled with millions and millions of dollars worth of rides - and I may be watching a wonderfully put together stage show while I'm eating it. Sure, I can run over to Taco Bell and get my lunch for $3 or $4...and sit and stare at other cars in a hot parking lot, or sit inside a, well, Taco Bell.
I think people are spending less everywhere; just take a look at almost any industry. I think that pointing the finger at Kings Island without looking at the big picture is a just little narrow in scope.