99% of businesses use Windows on the desktop.
Linux works great for certain applications and servers. But on the desktop? Not gonna happen.
Linux works fine on a desktop. There are over 200 different distributions to choose from.
According to Wikipedia, Linux has 20,000,000 lines of code, 14,000 programmers and cost (if the volunteer workers were paid wages) over $1-billion to develop.
Check out Distrowatch.com for reviews of various versions of Linux. Some dedicated to servers, some desktops, some to old computer hardware, etc.