There is 100 billions USD needed to rebuild Gaza.
Appartments, streets, powerplants, hospitals, roads, schools, bridges, railways etc.
Maybe a airport, a boulevard, a shipwreck etc.
No country on earth will invest 100 billion USD, just to watch it get destroyed after a few months of years, and then again invest 100 billion USD etc.
As long as Israel is alive and the Palestinians dont have airdefence, airforce or nukes, they can build nothing and are forced to live in tents.
No country want to see her investment blown up every year by Netanyahu.