Windows PCs have two advantages: you can do some cool stuff on them because of the range of software available, and they're cheap.
The bottom line is that Windows is a terribly designed OS from a technical standpoint and that's why there are all the problems. Yes, you might be able to maintain a good machine if you run 3 different antivirus apps in the background constantly and reformat regularly, but you shouldn't have to take those precautions. You shouldn't have to reformat unless you want to for some reason.
The file system on a decent OS doesn't degrade randomly over time and there shouldn't be a registry that can get corrupted; random browser exploits shouldn't be able to silently escalate to root; the browser shouldn't be shipped as part of the kernel FFS!
The reason that most people are more efficient on Windows is because that's what they know. If you spend some time kicking around on different OSs and desktop paradigms, you'll start to find Windows quite maddeningly inefficient from the perspective of desktop design too.
However if you spend most of your time working in Windows-only apps then it makes sense to use a Windows platform. You use the best tool for each particular job.