First of all, if all off-campus training institutions disappear, the impact on students will be complex. On the one hand, students may feel lost because they enjoy learning new skills and knowledge outside of class. On the other hand, students may have more time and opportunities to participate in other activities, such as sports, arts, and community service.

Secondly, parents will also be affected. Many parents believe that off-campus training institutions can help their children gain better educational and career prospects. If these institutions disappear, parents may feel confused and upset because they don't know how to provide better education and training opportunities to their children.

Finally, society as a whole will be affected. Off-campus training institutions have become a huge industry, which has generated a large number of employment opportunities and economic benefits. If these institutions disappear, many people will lose their jobs, which will have a negative impact on the economic and employment situation of society as a whole.

To sum up, the disappearance of off-campus training institutions will have a negative impact on students, parents and the entire society. We should be looking for ways to solve the problems with off-campus training institutions, not eliminate them. At the same time, the government should also strengthen supervision of these institutions to ensure that they provide high-quality education and training services to students and parents.