For people who just let it happen, they never really seek a residence to accommodate their needs in aging. The home they have now could have been obtained at any age, but they didn't select that home because it provided well for what they perceived their needs to be as they age. It may turn out to be a great home and one that will serve them well, but they didn't go into the relationship with this in mind. It was not why the home was acquired.
They could have had several different reasons for selecting their current home. It could have been the location - on acreage, in a nice urban neighborhood, in an older historical neighborhood, in a mature area, or in a gated residential community (golf course or not). Maybe is was the address - having a well-regarded and perceived status. It certainly could be the number of rooms, the size of the home, and the general layout. Nevertheless, it meet their needs - completely or mostly - when they bought it or moved into it.
The home could have been selected as much or even more for the outside - the architectural design, the size of the yard, the driveway, the backyard, the pool or summer kitchen, for instance. It could be that the yard is compact and easy to maintain. On the other hand, maybe the yard is quite spacious with room for planting trees, flowers, or a garden - or just keeping it as mostly open space around the home. It might already have had a garden, detached garage, office space, a garage apartment, or other features that made it attractive.
On the inside, there might be multiple levels with stairs, a large kitchen, several bedrooms and bathrooms, perhaps a basement, a media room, and even more - all of which worked for them when they moved in. Or, it could be a home of just a few rooms - maybe just a couple of bedrooms. It could be on one level.
The point is that many people may just one day find themselves living in a home that they like and that they discover meets many of their needs as they grow older and age-in-place without having done anything intentional about getting to this point. They like their home and don't want to move.
Conversely, many people find that they like their home for many of the reasons that originally attracted them to it, but it doesn't serve them so well anymore. It might be the stairs, the layout, the internal traffic flow, how easy it is to get through doorways or to open windows, and how well they can use the bathrooms. It could be many other features in the home that now are affecting their overall satisfaction with the home.
Without someone like us to come along and help them evaluate what is and is not working for them, people will continue to live in - and struggle with - a home that met their needs years ago but no longer does so in an effective way. Of course, they have to recognize that their home is failing them in some respects and that they want to take steps to change that so they don't need to move. They are onboard with remaining in their home, but they want it to be friendlier to their current needs.