This assumes they're going to leave enough people alive to even enact vengeance. If they murder everyone, than there's no need to worry about any Gazan revenge; there will be no Gazans.
It's very plausible. Keep in mind that from the get-go, the major global powers, (including Russia!) have adopted the mindset of Israel can do no wrong, and we can't criticize them at all
Israel could glass the entire Gaza strip and the reaction would be a slap on the wrist at best.
There's millions of Palestinians living in the West Bank or as refugees abroad, expelled or descended from those expelled in previous rounds of ethnic cleansing. Even if IDF go final solution on the 2 million Palestinians living in Gaza ghetto, this will not be the end of all Palestinians or the Palestinian struggle. See: https://en.m.wikipedia.org/wiki/Palestinian_diaspora
