>>102981900Most Kryptonian lore origins have them be a tyrannical empire, have them get their shit kicked in by an unspecified cause, they retreat to their planet without being more conservative with their resources, and they die either due to sheer ineptness, denial, or the belief that the universe should no longer have to suffer them.
If there was one thing that MoS did perfectly, it was hints of Krypton's lore. I don't even care that Kryptonite wasn't a thing, it's literally just an extension of a MacGuffin trope at this point. Now that's never happening, because Batman just had to be a wanker.
As for the Titans, I imagine something happened on Titan that Thanos wasn't aware of. Resource wars generally don't result in noone surviving by running, or gravitational disturbances. My headcanon is that Death itself intervened, and caused shit to hit the fan when solutions started being drafted, and the old guard nominated themselves to be sacrificed for the future.