It would have been done a long time ago if it were possible.

The more Palestinians die in Gaza now, the more recruits Hamas will have. The more depriving conditions for Palestinians in Gaza will be, the more time they will have to make new babies, who 20 years later will join the fight.

Besides that, you bring up a valid point that Israel is on the way to self-destruction.

I elaborate on the same issue in my recent article.