In my opinion, on the one hand, it's because branded designer items usually have the best designs in the whole fashion industry as they are the trendsetters. On the other hand, branded designer products are a symbol of wealth and success. People want to look trendy while thinking they are important. Others do treat you differently when you dress better. However, people who wear luxury items are no longer as rich as they look because according to this informative post about 1:1 AAA Gucci, people can pay one-tenth of the original prices for items of pretty much the same quality. So it's very possible that the seemingly luxury items used/carried by people around you are also fakes. Why pay more when you have access to a cheaper option?