My answer is just what you've implicitly said: "my life is compressed". Your brain "compresses" information better as you get older. It builds up a dictionary of experiences, thoughts, sights, sounds. Encounter the same or similar sensation again, you just get an index of the previous experience.
I suppose if you forgot a lot, you'd have to rebuild your "dictionary".
I suppose if you forgot a lot, you'd have to rebuild your "dictionary".