No, insulae were where everyone except the wealthy lived in urban environments including the upper middle classes. And what you're describing is what my city calls "mixed use" and is a corner stone of how apartments work in a lot of modern cities. Small apartments packed in tight above commerical spaces, with the commercial spaces disconnected economically from those living there except from sharing a landlord. The largest difference to today being that the moderately wealthy (ie. upper middle class that still lived in insulae) preferred the lower residential floors, which is a trend that continued until the advent of elevators.