Why did cars become popular?

Before automobiles, people walked. Not everyone had a horse and buggy, plus horses were needed for farm labor, not "going places" unless absolutely necessary. Getting some place was harder to do. People had to live close to cities because "downtown" was where shops and city offices were located. By the late 1800s, they still walked. By early 1900s, they rode trolleys to the places they were going. Going on a trip, even to the city just 10 to 15 miles away, was harder. Trains were used locally and for distance trips, or ferries and ships. But these took longer to get someplace. There were no malls, shopping centers, school buses, city buses, or urban development. The automobile gave people freedom to do what they need or to go places. I challenge you to live a week without using a car for anything. Doing that will help you understand this answer.