I do not think the David and Goliath story is 100% myth, a "fairy tale."
I think Israel learned from Hitler not to try to exterminate a people too quickly, and best of all, to try to make it appear that they are committing suicide - doing it to their incompetent selves. That way the world will only protest occasionally or UN only pass a few resolutions of condemnation. The process of extermination can continue, but slowly; Unfortunately, Israel must let the terrorists kill a few Israelis every year to justify the High Kill Ratios, the periodic shutting off of electric power, the collection and holding of their taxes, the periodic expansion, especially into the mountain aquifer with the new "security wall," the permanent closing of all airports etc. etc.
Thus these smart people learned how to get away with the extermination that the world was to "Never Again" let happen. Israel could and did exterminate the Negev Bedouins more quickly (at least their culture has been exterminated even if only about 80% of the Bedouins are dead or dispersted to other lands, at present.) as they were already self-isolating and without any allies.
If there is any "fairy tale" here, it is your idea that the US will cut off all aid to Israel, stop sending them parts for their US helicopters or the missiles they fire into Palestinian apartment buildings etc. (All in "self defense", of course, as required by US laws.)
From their POV, you have to admit they are proceeding with their program, brilliantly. So brilliantly that the world will probably "Never Again" stops them from killing or driving into other lands ALL of the Palestinians, and eventually gaining 100% of their lands. Disgusting, but brilliant, simply brilliant.
What may stop Israel in a decade or so, is a much smaller force than Israel - microscopically smaller! (Actually too small even to be seen with an optical microscope.)
A virus. Perhaps the Ebola virus in aerosol form thrown from a high rise window in Tele Aviv by a suicide terrorist who calmly walks away, happy to be soon be collecting his Martyr’s reward.