Do you make money by selling mobile phones?

I have been running a mobile phone shop for six years. At first, it was good. I was able to repair, collect and sell cards, and I made some money. However, since 2007, business has been getting worse and worse. I'm also reflecting on myself. I also discussed with my colleagues (we are not enemies, everyone is very new, and sometimes we adjust to each other). Everyone's business is not good, and many colleagues have closed down and changed careers. There are reasons for the surplus of peers here, and more is the timing development trend of the communication industry. Personally, I think the era of making money is over. It is said that the main source of making money in mobile phone shops now is selling mobile phone cards. Because selling mobile phones is no longer profitable and difficult to sell, you are no match for supermarkets at all. Nowadays, large mobile phone stores sell brand-name mobile phones. Speaking of maintenance, it doesn't seem to work either. Mobile phones are worthless, and people don't want to repair them because the maintenance cost is too high. Moreover, my experience in recent years shows that the current mobile phone production technology is very mature, the product quality is better than before, and the probability of maintenance is much smaller. If you are in a place with a large flow of people and a large floating population, selling mobile phone cards will account for the bulk of the profits of mobile phone stores, with many numbers and flexible sales. It is recommended to buy mobile, mobile is the boss, and Unicom is always worse. One-sided view of an experienced owner ~ ~