Inevitably what happens after 5 years is that someone reports that the app doesn’t work well with a newer version of iOS or Android, and the person that led the engineering on it is gone, because much of your engineering org has turned over after 5 years.

Then a new person jumps into the old project, finds out that it’s had 1 active user last year, then they question why they have to spend a week bug fixing something for one end user.