Fact: if these people had been running to a decent cloud service, they'd probably still have their data. Really "don't connect backup to the internet" is like, fractally stupid. The more one digs the more stupid angles turn up recursively similar to higher level stupid. "Don't connect backup to the internet" means what to you? What about the computer itself making the backup? If that is connected it could get infected as well, now what? Everyone is just supposed to give up on all networks entirely because "hurr durr nothing on a network is secure"? Which is wrong anyway since security an economic equation, not some ethereal absolute. I hope you never give this advice to anyone IRL.
> if these people had been running to a decent cloud service
They thought they were.
> If that is connected it could get infected as well, now what?
That's what the physical write-enable switch is for. A hardware read-only device cannot be written to.
Consider that I worked on the 757 stabilizer trim gearbox. The idea is no matter what fails, the airplane lands safely. I've been trained to think that way.
Consider also that I've worked with computers for 45 years. I've seen about every failure you can think of, including fires and floods, explosions and earthquakes, viruses and phishing.
The most unreliable, by far, part of computing is the internet.