I have a big appetetite, yet cheesecake is one thing that never fails to fill me up quickly. A real cheesecake is one of the most filling foods you can find, so it is absurd to suggest that anyone would eat an entire cheesecake.
I got a friend's grandmother's recipe - it calls for tons of eggs, not to mention all the CHEESE. Even if you whip the egg whites and fold them in it is still heavy and filling. A teeny tiny slice is plenty, served with sliced strawberries and kiwi - our family of four can share one cheesecake with all our neighbors and still have more than enough.
I made a homemade fudge filled turtle cheesecake for a police picnic the other day. They were small slices, and believe me they could not eat more than one slice. You're very right about cheesecake being filling. One slice is all you need when it's so rich.
When I used to sell them to bakeries, people would buy them whole sometimes instead of by the slice. I know they didn't eat the whole thing in one sitting lol..