Earlier quoted context omitted.
Why won't we?
Because the increasing trend is that it is not financially viable for younger families to buy a home. So they would thus not have a mortgage to reverse in the first place. Rather, they would be stuck paying rent and hopefully have enough savings/Social Security/other income to cover it as long as they needed.
Future generations CANNOT keep growing like that. Be it by directed reproduction limits or global resource wars/pollution/plagues/extinction from the preceding the population will shrink.