Their strength in armaments almost doesn't matter; even if every tunnel is collapsed and every rocket launch site obliterated, even if a ceasefire is reached and the hostages returned, even if Hamas leadership capitulates, you still end up with two million angry people swearing revenge for the injustices they've suffered.
There are two stable equilibria that this can settle into: no grievances, or no surviving civilians. I think the former is the only hope although Israel is making all the wrong moves. I am sure there are right-wing hardliners who would push for the ethnic cleansing route, but most Israelis are peace-minded moderates who would never forgive that option, and so I really think that result would eventually collapse the state of Israel from the inside out, doing more damage than any Hamas rockets ever could.
What makes you think that?
You mention the Marshall Plan, but the Marshall Plan worked in part because of Germany's unconditional surrender and the Allies complete assumption of control of Germany. If Israel wanted to follow the same game plan, they would have to do what they are doing, until Hamas was utterly defeated militarily.
It's important to recognize that Germany's surrender was not conditioned on any aid or support or anything else. Imagine if the Marshall Plan had been started prior to Germany's defeat -- it would only have prolonged the conflict.