I think there are three reasons for this. First, lower prices. Today, because of technology, it costs less to make items, so they sell for less. When the price difference is small or when it costs more to fix an item than to replace it, consumers naturally decide to pick up a new one. Second, increased wealth. People have more money than they did in the past, and because of lower prices, they can afford more things. A hundred year ago, most people had one or two sets of clothes. Those clothes were valuable and expensive and formed a significant part of their budget. Now, you can get a nice sweater for a few dollars. It isn’t expensive at all. When that sweater gets a hole in it, you toss it and buy a new one because you can afford to.