Food replacement is only one small part of energy backup. From TV, lights, heat, internet, AC, pond pumps etc. There are many different things life runs on besides the fridge, especially now that so many of us are working from home. We have 11 koi (with our new baby born last year!) that eat out of our hands, I'd be devastated if they died if the air pump and filters went dead for 24 hours.Even so, is a few hundred dollars worth of food replacement worth 20 to 30K worth of batteries?
Back up generators are nice, I've used them on and off for a decade. But they are a pain, and when Sandy hit us and gas lines formed it wasn't pretty. When fights started to regularly break out on the lines I knew the method sucked (and I needed home protection). For you only the fridge matters, for many others that is one small part of it. And they don't cost $20-30k net. After taxes and incentives they could be much less. I paid $8600 for 3 walls after all credits and discounts.