Sun City, Arizona. I presume most of those dwellings are single-family (or single person) homes. The top comment at the via is about the nightmare of delivering pizzas.
A relevant article at The New York Times discusses "living apart together (LAT)," whereby senior citizens "partner up" without living together.
Cohabitation, for example, is more often replacing remarriage following divorce or widowhood, said Susan L. Brown, a sociologist at Bowling Green State University in Ohio.These older adults are seeking (and finding) love, emotional support and an antidote to loneliness. But many older women, in particular, fear that a romantic attachment in later life will shortly lead to full-time caregiving...“A big attraction of LAT is to avoid the potential responsibility of being a full-time caregiver,” said Ingrid Arnet Connidis, an emerita sociology professor at Western University in London, Ontario. “Women cared for their children, parents and spouse, and want to avoid getting into these traditional gender roles.”