Because the comparison between 5G network and 4G network is completely different from that between 4G network and 3G network.

At first glance, the 5G network seems to be far superior to the 4G network because of its high speed and low delay, but it also has its own fatal shortcoming, that is, its poor ability to penetrate walls. This is because of the characteristics of 5G network, and there is no fundamental solution to this problem.

If you want to have 5G signals indoors, what operators can do is to lay small 5G base stations indoors as much as possible.

However, it is difficult to extend indoor base stations to all indoor places, such as users' homes. Users often use their own WIFI at home, and it is difficult to persuade them to install a 5G device at home.

Therefore, the 4G network still has a place in the 5G era, that is, in a closed space without indoor base stations. For example, a large office building is better than an indoor room where a 5G base station does not need to be installed separately.

For a long time to come, 5G networks and 4G networks will coexist. Unless one day, operators overcome the problem of poor penetration of 5G signals through walls.

But as I said at the beginning, this is only a theoretical prediction.

Although the three major operators are state-owned enterprises and have certain social services, they are still profitable enterprises, at least the losses should not be too ugly.

Therefore, operators will inevitably focus on more profitable businesses, such as the upcoming 5G, and for those businesses that are already somewhat outdated, their investment in them will be greatly reduced.

The 4G network is such a somewhat outdated role. Therefore, almost all major operators have suspended the development of 4G services, and now they are doing routine maintenance.

However, no progress is the biggest retrogression. There are more and more mobile phone network users, but there are still so few devices. In the long run, there will inevitably be poor 4G signals.

To be precise, it has begun to appear now. It is the best proof that the 4G network has been rolled out for so many years, but it is far from reaching the theoretical speed.

So the conclusion of this problem is: after the 5G network is rolled out, the 4G network will still exist as usual, but it may get worse and worse.