I don't agree. I think it is, at best, a wildcard.
Even if there is no demographic timebomb it is foolish to try and control large hostile Arab population centers. Doing so is costing us far too many good Israeli lives in pointless conflict. I say pointless because holding places like Gaza with no role in Jewish history, no religious significance, and only a tiny Jewish population vis a vis a huge Arab population, does not serve our security needs or enhance Israel's ability to defend itself IMHO.
You identify yourself as a "Likud supporter" in supporting return of Gaza. Plenty of Likud oppose returning Gaza including Netanyahu.
The "pointless conflict" comment presupposes that returning Gaza or anything else will stop the conflict. That decision is not in the hands of Israelis nor am I so naive that I believe the Palestinians will be satisfied with any form of two state solution including return up to 1967 borders.
It is just a form of appeasement perceived by Arabs as weakness.
In my view rather than needing protection which many Left leaning Israelis oppose, the Israelis who live in Gaza and the West Bank are a first line of defense. Even if one removes religious reasons from the equation, for strategic reasons they are crucial.