I gotta say, I think this is terrible advice. Buying a home and paying a mortgage is often cheaper than monthly rent. So, you actually don't have "surplus funds" with which to DCA. Renting for 30 years and you now have zero money as capital, just 30 years behind you. Paying off a 30 year mortgage you have 30 years behind you and a home to sell.
I gotta say, I think this is terrible advice. Buying a home and paying a mortgage is often cheaper than monthly rent. So, you actually don't have "surplus funds" with which to DCA. Renting for 30 years and you now have zero money as capital, just 30 years behind you. Paying off a 30 year mortgage you have 30 years behind you and a home to sell.