I honestly don’t think letting go implies giving anything up! I see it as letting go of the emotional load of some memories, but not of the memories themselves. I still choose to remember everything which happened to me, because it’s my past and I can do what I want with it, I just don’t let them burden me with emotions past their Best Before date (which is nonsense in practical terms, but I’m using it metaphorically).

Plus letting go of some things makes room for new things, like how one will never appreciate a current partner if they’re hung up on an ex. I see the same thing applying to everything else, including humanity ourselves! The old must always let go in order to make room for the new.