People lose interest, people change, people die. Software is a reflection of user problems, and users are alive, therefore software must adapt. Software from 1960s can't solve problems of people from 2020s, even if the concept is the same, the binary format is different - OSes are different today. The same solutions had to be adapted to new environment just because the environment has changed.

If we'll stop trying to find new users and we'll only try to retain old ones, we automatically have a declining userbase. This is not healthy for any software project, any country, any group.