Because treasury prices don't go up. You pay 100 and you get back 100 at maturity. Over long term, house prices are supposed to go up at inflation rate. So it's not a fair comparison between rental income and treasury yield. You have to compare total returns.
Will house prices go up in the next few years? I don't know. But you are trying to make your point based on historical data. So we should use historical data to make judgements. And clearly housing price keeps up with inflation over long term. No one knows how future will turn out, whether it's housing price or stock price.
