I think if it was announced now that at age 70 you loss your licence. People would protest for awhile and people would have talks about losing their freedoms. In a short few years, it would just become common and people would not only accept it, they would come to expect and plan their life around it. Perhaps moving to locations with good transit systems, or maybe even assisted living homes. I think a lot does depend on health, but it would make the law or regulation, almost impossible to regulate if you had a 1000 loop holes. Sometimes, for the greater good, some just have to grin and bear it.