In some instances, first drafts are probably good. Some are geniuses at the art of writing their lives. Some seem to “get it right” the first time: Fluid sentences in support of a solid plot on a unified theme written coherently. Are you one of those authors?
If you look at any work closely enough, you can see something worthy of revision. Maybe the work has too many complex sentences where simple ones would suffice. Maybe the opposite applies. Well, even if the work seems fluid, unified, and coherent, certainly there is no harm in revisiting it. A tweak here or there, a bit of reorganizing structure, or a plot shift might come from the muse of life. The sources of inspiration change with experience and age just as sure as generations of graffiti artists overwrite old graffiti.
Those who despair to any degree should realize that they can pick up the pen at any time and start rewriting. Even those who are just slightly unhappy can do the same. No author is bound to produce a single edition. Every author can erase the old and rewrite.
Everyone can be a palimpsest.