They still existed because they weren't disposable. You could fix them with tubes and the TV repair guy would go right to your house to fix it. (house calls). The seventies started to see a more common sight of smaller Color Tv's. Most of the big units were either black and white or converted color but by the end of the 70's the color ones were far more popular but more expensive thus the reason why they bought the smaller ones to save money. There were so many years that people didn't want to part with their console because it was considered a prestigious piece of furniture so they bought a smaller color set and just put it on top of the console.