We have had decades of excercises like "Excercise Cygnus", The Johns Hopkins Center for Health Security "Clade X" and "Event 201" plus near misses with H1N1 and MERS but still failed terribly in many critical areas. Some lessons will be learned from this but I'm almost certain it will not be enough for something with a higher CFR. Look at where Covid-19 is on this list
https://en.wikipedia.org/wiki/List_of_human_disease_case_fatality_rates - Now, imagine we dealt with something more menacing, the world would probably resemble an apocalyptic movie today.
As for a power back up. I bought a relatively cheap unit for power cuts, I paid £999 for it just under a year ago but you can get it for £799 now
https://maxoak.uk/products/bluetti-eb240-portable-power-station - I was looking at more expensive units with a larger inverter as that's only 1000w but it's for emergency use only plus it's 2400Wh. Will run my fridge-freezer, modem, PC (browsing only), TV and a couple lights for close to 8 hours.