Not true. Perhaps you’re confusing mining with custody. It costs nothing to park bitcoin in a software wallet, and you can buy one of the finest hardware wallets in the world for $60. You can sign transactions offline on self custody wallets, and it doesn’t need to be a ‘stable’, 24/7 internet connection. You just need an internet connection of some kind. It could be your mobile device.
If you’re supposing a large internet outsge, it doesn’t affect your bitcoin. It sits there waiting for you for when you can connect again, and if it’s some kind of major, region wide internet outage, that’s not likely in any real sense. That’s not really how the internet works, but even in that case, a Starlink terminal solves that completely if you’re preparing for a total, Mad Max-style Apocalypse.
Sure, keep a lot of cash on hand for emergencies, but cash is not a store of value. It loses 12% a year.
It will certainly depend on whether the digital infrastructure will be maintained during said economic collapse.
There is no digital infrastructure to maintain with bitcoin. As long as there are nodes running somewhere on planet Earth, everything is safe. I'm not sure what you think the alternative is in some sort of super unlikely apocalypse. Corporate banking? Equities? Bonds? Commodities? I'm sure you could stockpile barrels of oil or frozen concentrated orange juice, but good luck offloading it with no trucks to haul it off or digital banking to pay for it. Equities? With no stock exchanges, what good are they? These things are all destroyed much more completely in the event of some sort of global digital blackout, and good luck lugging around hundreds of pounds of precious metals, or exchanging them for anything of worth if there's no power.
Do the various hacks of exchanges or crypto company collapses not count as a potential risk?
No. These are not actual crypto holdings. Your crypto is held in large wallets controlled by the exchanges and sitting in a faux-wallets that can be compromised as easily as anything else with an Internet facing login. An actual bitcoin wallet can't be 'hacked' in the traditional sense. Someone has to have your private key or seed phrase, and this can only be compromised by sloppiness or carelessness.