If everyone is completely honest to themselves, there won’t have been anything called memoir or autobiography. But there are so many. The authors could have been great actors, actresses, screenwriters, or novelists.
Not everyone’s life deserves to be written down. Most people don’t have the heart to look back on their past. The few who wrote it down meant it as a diary or journal they knew would be for the public eye from the beginning.
When I get old, I won’t bother writing a memoir. I guess I will still write one poem each day and try to keep my doctor away.