If Cedar Fair did not think their pricing was more profitable than that of other parks, they would lower the prices. They aren't stupid.
And about Disney... their drinks are cheaper, but the food itself seemed to be more or less than KI. At Magic Kingdom, the fried fish basket I had was a bit less than it would be at Outer Hanks, but the fried shrimp basket was about a dollar more. And their buffets are certainly more.