Regarding break$-$even analysis, a good marketing manager knows that

a high fixed$-$cost contribution per unit will lead to high profits. assuming a straight$-$line total revenue curve incorrectly suggests that any quantity can be sold at the assumed price.

break$-$even analysis is useless for comparing pricing alternatives. the usual straight$-$line total cost curve applies only when economies of scale exist.

a break$-$even chart is a complicated visual aid for computing the break$-$even point.