Most people don’t use Linux on their personal computers. I would say that most businesses don’t use Linux, either. Windows by far has the greatest share of users, followed by Apple. And yet, Linux is used by many corporations, universities, and governmental agencies.
Linux is used by CERN and NASA, for example; the US Department of Defense, the US Navy, Whitehouse.gov, the New York Stock Exchange, the FAA, and the US Post Office.
Some of the larger corporations using Linux are Google, IBM, Amazon, Facebook, Twitter, and Wikipedia.
Although using Linux can save a lot of money, many of these organizations are large enough that the cost of operating systems wouldn’t have much impact. Certainly it’s nice to save some money – millions, in some cases – but more important is that the software is reliable and unencumbered. Linux systems are reliable.
I’m guessing that the freedom from encumbrances is probably one of the more important benefits that these organizations consider. They can pretty much use Linux and its associated software in any way they like, including modifying it to suit their needs. If there is a bug, they don’t have to wait until some company feels like fixing it. They can do it themselves.
Linux is now used by all of the top 500 supercomputers. Supercomputers are highly specialized hardware that require their operating system to be optimized. A proprietary operating system would be difficult to optimize, as well as expensive.
Linux is used by about 38% of websites. Somewhat less than half (47%) of software developers use Linux. Smartphones that use Android are running a modified version of Linux. It’s everywhere.
Despite this, Linux isn’t used much by desktop or laptop computers. Windows still reins supreme, with Apple a distant second place.