[slothtrop]

Couples who are 20-30 years older are also likely to move out in the next decade, with young families coming in. Depending on the build of the houses. Often there comes an age they don't want to deal with stairs, extra space to regularly clean, etc, or they are physically incapable. Of course if the area has no sense of community (i.e. rec centers, parks) then it might not appeal to younger people who want to start a family.

[bombcar]

It can happen, but I've also seen areas that have been consistently "newly wed or nearly dead" for 50+ years.