Interesting article with some sage advice. Buyers don't buy, unless they perceive greater value than the price being offered. Sellers don't sell, unless the price being offered is greater than their perception of the value of their own business.
That is, it is doubtful that both sellers and buyers are transacting exactly where marginal benefits equal marginal costs. Both likely perceive marginal benefits that are greater than or equal to marginal costs and some degree of economic surplus in the transaction.