In this case you can still lose hour worth of data. Multiply this with whole city/company scale. Paying a ransom for preventing this much effort going waste would still worth something.

Then these are incompetent people who forget to multiply the cost of the ransom by the amount of times it will likely repeat if they don't refuse to discuss with abductors.

It's like saying "why would we put this guy is jail? He's committed a crime but it's done now". Yeah, sure. Except without a deterrent he'll do it again tomorrow. This is the same except it gets rid if the motive instead.

There are such products for Windows, it's even built in. It requires the sysadmin to set it up though, and therefore is non functional in 99% of deployments.

Snapshots (not incremental nor differential) that take space proportional to change (1 byte change in a 5GB file takes 10K or so in backup, even insertion/deletion), built in to windows? How is it called?

TimeMachine in macs has a similar feature set notably lacking proportional space (insert 1 byte anywhere in a 5GB file and the snapshot takes an additional 5GB)

Can't say I'm sure about the actual space usage, but the subsystem is "Shadow Copy". https://en.wikipedia.org/wiki/Shadow_Copy

That’s a low level mechanism that is used to implement consistent backups, (comparable to e.g. LVM snapshots for any file system or ZFS/Btrfs snapshots) but it does not offer anything directly to end users. The venerable built in NTBackup (afaik the only built in user backup system included in Windows) is better than nothing but is a far cry from Borg/Bup - it is practically infeasible to snapshot e.g. every hour.