In theory, it means that young families should buy the absolute maximum house they can afford. Stretch and limit spending in every other area as much as possible, then hold it as long as possible. Then "old people" can sell and downsize to trade space for cash.

Looking back, it seems like a lot of places looked a lot like this for a long time. It is fairly recent that we see people swapping every 4-7 years, at surprisingly high cost.