The free enterprise country has flourished while the more controlled country is an economic disaster. Look at our sister industry - site built homes. That industry is still dominated by the give and take of offer and counter offer. If single pricing worked, realtors would simply post a price on the for-sale sign and wait for a deal. Look also at other large transactions such as art auctions.
History seems to show that in large ticket transactions, human nature wants to haggle.
Let's take an auction for example. A few months ago, my wife and I attended a livestock auction just for fun. We didn't want livestock and have no use for any but were out for a day in the country. After a while, a small goat came up for auction. The bidding then started in earnest and the auctioneer skillfully raised the price.