The danger for consumers is assuming this is a zero-sum and that the converse economic goal applies to you (i.e. assuming that the consumer benefits by eating a lot or focusing on meat). I conjecture that after factoring in the economics of health and quality of life, the economic optimum for a typical buffet consumer is the same as for any other eater: to eat sparingly and in a balanced manner.
Buffets feel like an unbounded solution to optimizing for calories per dollar, which is a ridiculous thing to focus on as an overweight engineer!
Optimizing expensive-food-per-dollar would hit the meats, rather than the highest-calorie options.