In a seller's market, the seller might raise the purchase price to compensate for the costs of the buydown, but in most markets, it would not be to their advantage to use a buydown as an enticement if they are going to offset the benefit by raising the price. In most cases, the buydown does not involve the seller - it is an arrangement between the lender and the buyer.
In a seller's market, sellers might increase prices to compensate for the costs of a buydown, but in most markets, using a buydown as an incentive wouldn't be profitable for them if they plan to offset the benefit by raising the price. In most cases, the buydown is not initiated by the seller; it's an agreement between the lender and the buyer.