I don't think this is true. Housing has basically been around 50% of total wealth for the past 50 years or so. Check out Pikettys capital in the 21st century for far more details.
there is a clear point at which one might start thinking about real estate as investment (and it sure looks bubbly). if you bought a house as an investments some decades ago it is not much of an investment and basically a loss inflation-adjusted, no?