Numerous analysts have said that "Israel will not allow a full-blown humanitarian crisis in Gaza". First of all, I am not sure how they would define a "full-blown" crisis. Can the current crisis reach "half-blown" status at least? The place is rubble. Sanitation, electricity, and drinking water facilities are destroyed. Hospitals are destroyed. The systems were brought to the breaking point by blockade and then pushed over the cliff by systematic destruction. If people are starving, how would anyone know? They shoot journalists and bomb UNRWA, after all, including reserve food stocks and supply convoys. And the world's journalists and the UN mostly apologize for getting in the way of the bombs (while condemning the Palestinians for doing the same).
Here's another one I wouldn't assume: "Israel must withdraw eventually". Why is that? They occupied Gaza for years in the past. They want to see to it that Gaza cannot govern itself and that society there collapses completely. What better way than to continue to do what they are doing? Is it out of their reach financially, militarily, politically, or diplomatically? On the contrary. This operation was an experiment in what it was possible to get away with, and they have gotten away with it all. The next phase is the closely supervised destruction of the innovations Gaza used to survive for so long: the remaining infrastructure (schools, hospitals, roads, plumbing, electricity) the tunnels, the police, United Nations aid, the ability to share whatever was brought in through Hamas's social networks and organization (the social networks will be dismantled through arrest and assassination of leaders and terror attacks on civilians). The Israelis destroyed it. Now they must look after their investment and see that it stays destroyed.
All they need to achieve this is what they have already got: the compliance of the Western and Arab regimes. If these regimes allowed (when they didn't cheer) a month of high-tech high-intensity massacre, why would they shrink from months of occupation and starvation? And even if they did shrink, how would they accomplish anything effective to stop it? With a totally destroyed infrastructure, continued sanctions, and Israel's one-sided war against the UN in effect, we are well into "full blown humanitarian crisis", unless some unforeseen change in the balance of forces occurs.
It bears repeating that it would be easy enough for the US to deal with this. They could say no more weapons for Israel unless Israel leaves Gaza, ends the blockade, and allows complete freedom of movement for people and goods; no Israeli authority over Gaza's airspace, sea lanes, passage of its people to the West Bank or any other country, or its border with Egypt. This is so minimalist that it is painful to argue for it, but it is all the same completely inconceivable that even this supposedly hope-and-change-oriented administration would do it.
Grassroots efforts to change the balance of forces and impose some cost to the indecency of Western political leaders on this issue are racing against time. The Palestinians are without protection.