It doesn't.

If Israel did nothing now. Just focused on itself and ignored the external, would the the Iranian regime give up its ultimate goal?

This is the elephant in the room. I will reiterate the premise here:

The past has happened.

Both sides have done heinous shit.

Both sides have fanatical elements that are intent on their goal.

Does one side give up on that goal mean the other side will?

We annot go backwards, we can only go forwards, and if we find ourselves posing the question "what do you expect them to do" then the same question applies to the other side.

Unless somehow we are suggesting the Israelis are somehow more capable of recognising the death spiral they are caught in, and are the ones who must change? ( While ignoring the question I posed above )