You don’t share food if you’re starving. You don’t share time if you work 12 hour days, every day.
If you spend all your energy on survival, you got no energy to spare on anyone else. I bet our hypothetical starving person would be moral and share, if they had the chance and materials.
If they don’t… then it’s not a matter of won’t it’s can’t. People are more likely to share food they have excess of, time they have excess of. If they can’t spare it, they won’t.
Why does it need to remain? It seems like solipsism to assume it must remain because it’s your point of origin. If something or someone has the power to drop something into the past why wouldnt it overwrite everything? I don’t see why consciousness even gets applied. The universe keeps on whether I am alive, asleep, or dead.
I see the path of time like a laser beam in a house of mirrors. If someone has the power to add a mirror somewhere. Yep, the whole beam after the fact is a vastly different pattern. Any multiverse would be entirely virtual and theoretical.