An old idea, the boardinghouse, might be a good solution for mostly independent seniors. It makes a lot of sense especially for single seniors, like widows and widowers, to keep them plugged into society and help avoid isolation. Buildings with independent apartments that seniors can retreat to for privacy, but shared kitchens, gardens, and gathering places, could be really interesting options. Unlike retirement villages you wouldn't be paying for services, just sharing the space with others. And since you're sharing spaces the cost of the individual apartments should also be less than a standard apartment rental. It feels like this concept could have interesting possibilities.