Those who tried Linux and went back to Windows, what caused you to go back to Windows?

"Why else would so many businesses overlook a completely free operating system"

Well, they don't. Plenty of businesses use Linux systems. It's not (only) because it's free, though. The issue of licensing often isn't a factor that comes into play over having a system that just works. It's easy to customize, flexible and comparatively secure. Your experiences with Linux are valid, but many businesses and individuals do use it daily and for good reason.