A lot of people who use a computer for work purposes have a number of software applications that they must be able to run reliably in order to do their job.
The problem is steadily getting better in some areas, but there are still thousands of specialist applications in service today that only run on Windows. If you are lucky, there may also be Mac versions.
The reality is that it's often not feasible to only run FOSS, and nothing but FOSS.
Wine has been up to real-world commercial use for at least a decade, in my experience. It's more surprising these days when stuff doesn't work in Wine than when it does. (.NET support is still annoyingly imperfect.)
Sponsoring getting a vertical market app working 100% in Wine is unlikely to be cheaper than cleaning up after WannaCry's competently-written successors.
The problem is steadily getting better in some areas, but there are still thousands of specialist applications in service today that only run on Windows. If you are lucky, there may also be Mac versions.
The reality is that it's often not feasible to only run FOSS, and nothing but FOSS.