Israel will do whatever it has to do to prevent Hamas, Islamic Jihad, etc. from ever being able to launch a large scale attack on Israel again, so if Hamas, Islamic Jihad, etc. surrender and turn in all their weapons, the fighting will end and no one else will die, but we all know that will not happen.
Hamas has built at least 350 miles, and perhaps as much as 500 miles of military tunnels under this tiny strip of land, so that nearly every building in Gaza is built atop or near a tunnel or tunnel exist that must be destroyed, and that means civilian casualties will continue to be high, but since Israel is abiding meticulously by International Law in this operation, you can take comfort in the fact that the number of civilian casualties is the minimum necessary to complete the mission of destroying Hamas' ability to launch large scale attacks on Israel.
Gaza, the West Bank, Including East Jerusalem, Golan Heights, were all given to Israel by the Arab nations that chose to launch attacks on Israel from these sites. No do overs.