Why do you assume that, seems like a cash buyout would be a great deal for many sellers if it was at the appropriate price. Issue is I think that Zillow's information was less granular than what the buyers/sellers had. Let's say Zillow priced two houses near each other at 1million each. However one was close to a busy road so would only sell for $900k while the other could sell for $1.1. Zillow made the right average offer of $1million to both but the buyers/sellers actually had more information. So the 1.1m seller didn't take Zillow's offer while the 900k seller did. Now Zillow was out $100k essentially not counting fees.