I don't have any evidence either way so all I can do is appeal to common sense, but I can't imagine most of the organizations hit by ransomware didn't at least

I don't have any evidence either way so all I can do is appeal to common sense, but I can't imagine most of the organizations hit by ransomware didn't at least devote some extra amount of attention or resources towards IT security in response. At a bare minimum I'd expect them to at least patch the vulnerability that the ransomware used to infect their systems. Are there any examples of orgs that have been repeatedly hit by ransomware over and over? Working backups are not enough to insulate you from this threat. If you allow an attacker to remain within your systems long enough you might find they've encrypted all your backups!