This is correct but you can do tricks to change who the counterparty is, which is often useful. If, instead of putting up a yard sign and saying "this house is for sale" and waiting for someone to come by and complete the transaction, the homeowners entered a contract with a brokerage to sell the house to anyone who is willing to abide by a list of terms (minimum price, occupancy date, etc.), then the brokerage can respond immediately and say "great, the house is yours". This is essentially the equivalent of sending a sell order to a stock broker.