As much as I don't like to say this, because it only invites adversarial comments,

[patphil]

but the leaders have probably all gone to "safe havens".
I don't think any amount of further conflict can eliminate Hamas. It will only insure that the next generation of Hamas is recruited amidst the rubble of Gaza.

What needs to happen is a change of the mindset of the people who live in Gaza.
They must be given protection from Hamas so they can rebuild with new leadership that isn't wearing masks and carrying guns.
And above all, they need to be treated with respect, and be given assurances that they won't be treated like refugees on their own land.
This is how the cycle can be broken, and both sides can eventually form a equitable and lasting peace.