It's not just Vail in the west either. Winter Park and Copper both charged me $23 for 2 slices of pizza and a water for lunch. Never seen anything that crazy in the east, Stowe included. But some (Killington, Mt Snow, probably Stowe now) are close.
I don't remember exactly but somewhere around $6 for a slice sticks in my mind from Killington/Pico this past winter.