If he killed Thanos and solved this 'known' problem, would an even bigger 'unknown' problem pop up?
In order to save people, the Avengers in 2023 had used the same move as Thanos in 2014.
Luke couldn't guarantee that there wouldn't be a backlash if he went to another 2023 through the Quantum Realm and came back to 'modify the plot.'
It made sense that the bigger the cheat, the more severe the backlash.
Also, there had been too many 'world-destroying' events in the last two years. It was very unlikely that he could completely stop the situation from developing.
Compared with those old monsters who had almost infinite lifespans, Luke felt that what he needed the most was more time to arrange everything.
At that moment, Robert and Catherine brought Cindy to New York.
Cindy was already 11 years old. She had graduated elementary school early, and was coming to New York to attend middle school.