In our house we have currently reliable (fibre to the cabinet, copper from there to the house) internet.
We have a mobile phone each, each with a different providers.
We actually only keep a landline phone connected because some elderly relatives call us on it, and that had dropped from 3 to 2 now my mother is unable to call. The chances of the internet and both mobiles failing at the same time is slim to non existent outside a societal collapse. And then we'll have other worries.
A couple of years ago, we had quite a long power outage in fairly rural Sussex. The outage was round 8 hours in total, but I was able to get us on-line periodically. I ran the ONT, switch and AP for 30 minutes at a time, this let everyone update their phones and tablets, download any media they wanted and catch up with friends and relatives. Everything was turned off for an hour in between.
I bought a 1200W petrol generator after this (in anticipation energy scarcity and societal collapse!), but I've not had reason to use it, yet.