My guess is that they meant: If you give a lot of people that previously couldn't afford a house more money it will increase the demand and prices. The issue is that there is a shortage of housing which is primarily due to zoning preventing the construction of houses in a lot of areas.
Ah this implies definition of wealth is purely $ value, not what their inflation-adjusted “afford to buy material goods and services” value.
for any given dollar a middle class/poor household would be more likely to spend it on housing or additional square footage than a richer household