Your argument is "well, the average home might not beat the average stock, but if you compare unusually good homes to the average stock then the result is different".
Well of course comparing unusually good homes to average stocks is different that comparing average homes to average stocks.
But if we're going to compare unusually good homes to something, compare them to unusually good stocks. Unusually good stocks do much better than 20%.
None of that changes the reality that on average, investing in a diversified portfolio of stocks will do better than investing in a diversified portfolio of homes.