Mainly geography. But also nobody else cares enough about Gaza to spend the time and money. The people that live there have no infrastructure or institutions in place to rebuild, let alone the materials and labor to do the work. Leaving Gaza to fix itself it not an option. Like where would Gaza even get the machinery or lumber if not from Israel?
Hamas’s international benefactors only give money if Hamas is fielding fighters and killing Jews. If Hamas is gone, Gaza is just another failed-state, thrid-world hell hole with no natural resources.
I’m not bursting this bubble for you right? Like where do you think this goes from here? Talking about, either a fully militarized border across which nothing travels and the famine everyone is concerned about comes to fruition and the death toll goes from 30,000 to 300,000, which nobody with any say in the matter wants, or Israel takes full control of Gaza for at least some period of time, maybe forever.
Right now Gaza is a warzone. When that is no longer true, it will at least remain under martial law while as the last pockets of Hamas resistance are rooted out and the last tunnels collapsed. It’s up to Hamas whether that takes one year or ten years. Hamas is in charge of Gaza and they do not follow any international laws or social norms. They will absolutely not be given a country to do whatever they please.