If the motorcycle were suddenly invented today, we would have a similar effect. A certain group of people would find the motorcycle very appealing. Compared to the car, they are small, more fuel efficient, and less expensive. So the set of people not needing an enclosed vehicle with room for passengers and cargo would all run out and buy one. In those first few years motorcycle sales would spike relative to cars, and probably displace some car sales.
Anyone looking at the sales figures and marketplace trends in those days would proclaim that the days of the automobile were nearing the end and that the car was doomed. After all, all motor vehicles are the same, right.
Actually, in hindsight, it might have been a good time to invest in cars.