Gaza will essentially be an enormous pile of rubble when the war is over. The Palestinians will be living in unspeakable misery. There will be no food, fuel, shelter, jobs, or sanitary facilities for the civilian population. Who is going to fix this problem?
Two possibilities can be dismissed immediately. First, the Egyptians are not going to permit the Palestinians to be moved to a new refugee camp in their territory. Second, the Israeli government will be in no position to fix the damage it is so busy creating. As usual, it will be demanding aid from the international community.
So who will fill the gap? The US and the EU will refuse to pony up unless the Israeli government makes a really serious effort to resolve the underlying political problem with the Palestinians. This is where Biden can really use his leverage with the Israelis. Most of the Arab states will react the same way. The Chinese don’t believe in charity, so they won’t help in any meaningful way. Qatar and Iran, both of whom have good relations with Hamas, will try to funnel in some aid, but the scope of the damage is way too great for them to handle. International organizations largely funded by the US and the EU won’t have enough money to solve the problem, either.
The current Israeli government has no interest in engaging in any serious talks about Palestinian rights. That means one of two things is going to happen: either the government is replaced by a new centrist one that is willing to engage in serious negotiations over a two-state solution in exchange for economic assistance; or the international response will be much too little, too late, and the misery will persist for the foreseeable future.
I would put my money on B.