When Linux provides so many high-quality operating systems of many varieties free of cost, why do people still buy Mac OS and Windows OS?
Generally, people don’t buy an operating system. When they buy their computer, they just stick with whatever operating system comes pre installed. In most cases, that OS is Windows. When people buy a Mac, they stick with macOS.
The majority of times where people buy an operating system is when they build their own system. In that scenario, people install Windows by choice. For example, those people are either gamers and/or video editors, and they need Windows for that reason. Other people who are developers install Linux. Some people go to the extent of Hackintoshing their systems.
As for the answer to the original question: Linux does not suit all use cases yet.
For example: if you are a video editor, Linux simply does not work for you. You either go with Windows or a Mac. However, if you are a developer, Linux is miles ahead of Windows. Same if you are a sysadmin.
It really depends on use case. And then there is always personal preference. I may like Linux but it may not work for you. People install what they like the best, and more importantly, what works.
Link to Quora: