It can be solved without going out. Why not go out? Going out also requires transportation expenses, which is troublesome.
Of course, many young people choose to stay at home, which must be related to economic reasons. Imagine that if you are rich enough, you can quit your job and travel around the world to relax, so that you can see the beautiful scenery around the world and broaden your knowledge. And staying at home can not only save money, but also have a lot of things to do. For example, watching TV, playing games and so on, so there are more and more otaku.
In addition to the economy, personality preference is also an important reason. A little extroverted and autistic, unwilling to go to places where people are too busy. This kind of people generally don't like places where people are particularly crowded, and they don't like to take long-distance transportation. So unless they lack what you want to buy, you won't go out at all.
Stay indoors for a long time and communicate less with others. Once you go out, you will find yourself out of place with others, so you don't like going out very much. The vicious circle is more and more reluctant to go out. Moreover, mobile phones and the Internet may develop, and many people forget the most traditional social ways. In the past, we needed to go out to make friends and establish new social circles, but now as long as we have a mobile phone, we can meet different people and get the hottest information through various software.