Prices aren’t controlled by realtors, appraisers, nor governments. Prices, in housing, aren’t controlled at all really. But to say that there are no factors that influence them isn’t correct, just the word “control” would, by most, be considered incorrect.
Houses are sold by one party and bought by another based on a negotiation and prices are basically based on supply and demand. Realtors, et. al., have a role in the negotiation, but they can’t overcome supply and demand, which is influenced by factors such as unemployment, interest rates, and market psychology. The prices are set by whatever the two parties agree on, it’s to the factors that effect that negotiation we should look to see hints of price changes.