Technically multiple bombs explode here and there. Here's how:

* Family bought 1 house (assets), big mortgage (cause it's expensive), live until retirement

* Parents sell the house (lost the assets) to either a wealthier family or investors to downgrade

* Parents potentially share the proceeding to the kids to support their Housing endeavor but Kids will be forced to buy something smaller (usually Condos) because detached is expensive and kids wage just starting from the bottom of the paygrade.

Long-term, middle class will erode.