Effectiveness can be rebuilt when there are more and more followers of an ideology. And more ruthless effectiveness as well. It's all fine unless and until something worse than IS is created instead with the same ideology, or, in this case something worse than Hamas, or, if we are lucky, Hamas just regroups. I suppose, if everyone is very lucky, what you are saying might just happen but, imo, it will be never ending unless the underlying causes are addressed, and that goes all the way to the US and Iran, the Arab States and, of course, Israel.
Just buying time at the cost of thousands of lives seems hugely callous.
Anyway, we don't have to agree on this. :)