I'm thankful I've never had a computer hit with ransomware, but I do know others who have. It's just another reason to back up data regularly and save it in more than one place. Various "analog" problems can take your data too. Hard discs can fail without warning. A thief could break in your shop and steal a computer. Perhaps the building burns down or gets hit by a tornado. Either way the computer is gone along with the data stored in it. If you have back ups on and off your work site you'll still have your data and be able to get operations back to normal faster.
Criminals are doing big business spreading malware. Ransomware is one of the most insidious forms of it ever created. Long ago "black hat" crackers did a bunch of this stuff for the fun of vandalizing other people's computers. Making money is the main incentive now. Some do the hacking for other evil purposes, like stalking. Every computer user must realize as long as his computer is connected to the Internet it is potentially exposed to all sorts of evil. No system (not even a Mac) is perfectly safe.
It would be nice if law enforcement could do something about this very costly problem, but they're largely powerless against it. Many of the black hats do their work in countries like Russia and China, where the US has no extradition treaties. So when the FBI, Microsoft or whoever is able to clearly identify a black hat criminal the police in those countries smile and do nothing. In the end the only defense is "white hat" crackers finding security holes and telling Apple, Microsoft, Google, etc. about them and educating end users to be street smart about surfing the web.
Some of my friends are into getting torrents of pirated movies, music, cracked software, etc. I warn them that's a very good way to get a computer system hosed with malware. Criminals put a bunch of that stuff out there as bait.