Communities like that ARE being built. There's one just south of Manassas, VA, off of Rt. 28. The down side is that it's not as close to shopping as I would like for it to be, but the premise of the entire community is that the houses are designed to accommodate the needs of those who are disabled, elderly, or otherwise need extra accommodation.

What the developers NEED is to hire architects with training in geriatric and disability issues, and not simply install spec. housing wherein the designer has not taken the changing needs of an individual as he/she ages or becomes less able-bodied into account.