That can get you sterile water, although it's extremely difficult to do and involves many more rocks than you'd imagine easily 5x the mass of rock to water to get a rolling boil for a full minute, but it doesn't get you clean water. Now you have sterile water with a lot of potentially very unpleasant dissolved solids. Certainly not something you'll be using to feed an infant.
Still, all the ancillary services that go into a hospital like water, sewage, medical gasses, cold chains, etc are all dependent on the grid, as are the people who make them work. If a large-scale outage happens, most hospitals will start losing patients within 24-48 hours and will close as functioning hospitals well within a week.
I think the subject of the thread is pretty clearly how to deal with interruptions that won't resolve themselves in a short time. It's on you that you choose to ignore that and focus on "was it pretty for a milisecond?"
Now we've gotten to "Ok the claim was admittedly not true but it's your fault for pointing it out instead of going along with the groupthink" Is this the post-truth society we hear about?
The sub-thread was very clearly started by the idea that loss of connectivity might not be as bad as assumed, there was space to have some debate about what positives could be taken and how we could actually prepare to live with outages alongside preparing to negate them.
I didn't think much of it honestly, the original point of it not being so bad, but your comment has left me with the feeling that the internet can't fall soon enough.
I'm not sure how far into "prepper" that makes me. I don't have a store of canned food or weapons or a generator. I started down this track to keep my home lab (on which I self-host a bunch of stuff) online / protected through outages.
Additionally, the city in which I live has an ad-hoc amateur WiFi setup which connects over several kilometres. I used to be a member a long time ago but, ironically (in this context) getting fiber internet meant I kinda lost interest. It's one of those things that had just never gotten back to the top of my priority list: https://air-stream.org/
Feels like they're ahead of game on this topic.
If you own a house I'd look into very old school options like digging a deep hole to store your food in a dark&cool place - forgot the name for it but it'll work for weeks or months without a single milliwatt
It's terrible in a society-collapse way - makes you a target.
A target for what? People to come charge their phone at your house?
Why would you be a target if 50%+ of population have solar setups?
Cities are not setup to support their current populations without those services and once you run out of buffer things go downhill quick - wastewater is an enormous and immediate disease hazard.
Otherwise you're throwing out all fresh food, supermarkets couldn't process payments nor most restaurants either, etc.