Companies generally do not have a sufficient tested backup strategy and plan (though backups have only one part to play). Those same companies have probably never suffered any major consequences as a result - which might explain why it’s so usual for this to be a common gap. Sloppy/incomplete backups can probably wing/firefight the more common ‘single server dies’ ‘single directory needs recovering from accidental deletion on file server’ ‘need to restore database following botched upgrade’ type scenarios creating a false sense of security.

In the same way companies do not have sufficient HA for their critical systems or processes. HA means being actively resistant to events impacting availability by having (typically automated) redundancy to remove SPoFs. It doesn’t mean HA owing to luck the server hasn’t died in 10 years owing to lack of/poor maintenance. But both with HA and backups companies can dodge bullets (until a real emergency) and maybe never even have a major incident.

Ransomware kind of exploits this lack of organisation level sufficient backing up of all critical information assets.

It really is as you say, low hanging fruit.