Detroit hasn’t always been a bus city (which I guess is still questionable based on current bus performance). David Gifford shared this map from Book 3, When Eastern Michigan Rode The Rails by Schramm, Henning and Andrews. In 1925, the Western suburbs really stand out with multiple bus lines stretching across Wayne County. There was similar heavy bus service in the Westside of Detroit, but not the Eastside. Based on the proposed Woodward line all the way to Pontiac I’m going to say there should have always been an elevated light rail built along M1.