Another way of looking at it, is driving around with a 1g can of gas in your ICE car. Who does that?! The gas and can would cost 10 dollars vs $4 - 5000 for the portable battery charge. And only weigh about 10 lbs vs 100. Would be better off carrying around a generator with a gallon of gas for an EV (not that anyone would do that either).
And most, if not all EVs sold today, come with free roadside assistance which includes a low battery recovery event. That seems to me a much better solution and insurance for that situation. Also, you would have to be an extreme idiot to let your car battery run that low without charging, given all the onboard alerts, data, and aids to prevent that, and also direct you to the nearest charging station. Plus don't forget that you can charge your car (slowly) at any 120v plug if you have to. At least that would get you up to a level to get to the next fast charger.