Israel did not understand Hamas strategy, likely not now either

Israel did not understand Hamas's religious nature, hence intelligence and policy failure.

And Israel likely is screwing up the current strategy, too. The ground campaign in Gaza likely will be very slow and high casualties, without even thinking about the Palestinian "collateral damage". The second Lebanon war shows that Arabs are now capable of conducting highly motivated and dynamic defensive operations.

More fundamentally, Israel cannot conduct an ethnic cleansing. The birth rate is against the Jews, too. They could have given up all of southern Israel earlier on. It is a possible result in the near future.