> Is it possible to bore for my own water supply, install solar+inverter/battery backup for electricity, get a medical degree to treat my own wounds? Sure but most would say it’s not reasonable.

Bad analogy. A better one would be having a torch in case of power cuts (done that) having some extra food in the house in case the grocery delivery fails, having some basic medical supplies in the house, having mobile internet connection in case your broadband fails etc.

Having backups of your stuff is an emergency fallback

Ordinary backups don't aim to replace the full service. When you have a stock of food, you don't have enough to last you a lifetime. You have enough to weather a storm. The equivalent for tech would probably be having an offline copy of your "essential" data, but not of every photo you ever took. It would protect you from temporary internet disruption, or if a provider suspended you for a few days, but not if they banned you completely with no recourse.