Why doesn't Superman make his own Flashpoint paradox to save Krypton?

Question

Why doesn't Superman make his own Flashpoint paradox?

• He knows about the Flash-based one, including the time artifacts
• He has the ability to time-travel
• He has said numerous times that he would do anything to save Krypton

He could try to save Krypton while still sending himself and Kara to earth, and thus preserve the timelines, story continuity, and the Kryptonian people. Instead of it being entirely destroyed, the rescued folks could be hidden/displaced.

He could even set a "flag", where his past self leaves an indicator to his incoming present self, and failure to find the flag at the right spot means failure, so desist. He would make steps back in time, and along the track, and leave flags about their progress for his future self to allow improvement, reactivity. If, in the long run, rescuing Krypton was a bad idea, he could go back, and pull one of his own flags, and tell himself "abandon ship".

• Why wouldn't he think of this?
• If he did think of it, why wouldn't he do this, to save his entire planet and people?

Options in approach:

• Go back in time 1000 years before the fall of Krypton, clone some Kryptonians, and put them elsewhere in the universe where they have a decent chance of getting back to the future.
• Go back in time 10 years before the fall of Krypton, and give his father measurement equipment and material, retrieve just before the destruction, then go back 100, or 1000 years and let them have the data for more than enough time to do all that needs to be done to save it.
• Pull a Dr. Who and teleport it to another place at the moment of its apparent destruction, or tuck it into a place like the Phantom Zone that is disconnected from the actual phantom zone. Or just tuck all the people into such a place - it is a much better option than being dead.
• Go rescue his family only, and do it 10 years before Krypton explodes.

There are different "scopes" of saved: family, people, beings, city, planet. They require different scopes of work and strategy. He has options.

Notes:

• In the movie his parents find it mentionable that the yellow sun will give him super-powers. This suggests that super-powers were not the norm on Krypton. It may be a planet of kryptonite, or the lack of a sun, give the Kryptonians substantially less powers than superman himself.
• Superman has worn protective suits to retain his powers in the presence of kryptonite. It might be a viable strategy to get his super-powered self to Krypton, retain his powers, and fly back "under his own steam".

Answer 1

Four Reasons

1. Krypton's Red Sun

Under a red sun, Superman's abilities are reduced to human-like levels. Depending on who's writing the story, it could take anywhere from a few seconds to a day or so but either way, it's unlikely he'd be "super" enough to do anything helpful for very long.

2. Kryptonian Skepticism

While the details surrounding Krypton's demise change from iteration to iteration, it's generally understood that it was Kryptonian pride/skepticism/ignorance that allowed the planet's destruction. Despite Jor-El's pleading, no one believed they were in any danger until it was too late. I don't see what a de-powered Superman could do to change public perception that Jor-El didn't already try.

3. It's Insanely Complicated

I realize we're talking about Superman, the guy that can basically do anything, but the logistics of implementing one of the solutions you mention are no walk in the park. Go back and read Booster Gold #5 (Feb 2008) as an example of just how hard it can be to screw with time to save 1 person who was shot a few years ago, let alone traveling hundreds or thousands of years back to save an alien civilization responsible for its own demise. There are so many unknowns and variables involved in cloning, hiding a whole planet in the phantom zone, etc. that the likelihood of success is very low.

4. Super Morality

The most important reason, if we're being honest. Even if Superman could find a reasonable, safe solution for saving Krypton, what makes us think he should? In every DC comics time travel story I've ever read, the moral of the story is always something like:

Don't f*** with time. You'll always regret it.

Every story - Flashpoint especially - ends poorly for those that try to manipulate time. Time either won't let you change events at all, time auto-corrects itself down the road, or the desired changes cause a ripple effect that screw up everything you've ever cared about. Whatever the narrative is, it's never "So-and-so went back in time, changed history, and lived happily ever after."

Because of this, any speedster or time traveler in the DC universe (Flash, Rip Hunter, Booster Gold, etc.) would advise Superman against trying. His above-reproach morality would force him to swallow his own desires - no matter how noble - and let the past stay in the past because he knows changing history would only make things worse.