Why is there no domestic computer operating system in China? Are software companies unwilling to do it because of low profits, or can't do it at all?

Yes, yes, it's almost the same as foreign countries. It's basically linux kernel, and it's already relatively backward on pc. People who use it are generally engaged in IT. Now that windows is the only one, there is no way. If your system is small, for example, if you use it as an electronic document, it may not open on the company's windows xp. At present, there are linux deepin and ylmf os that are doing well in China. New Kirin (I don't want to mention it), Dida linux (under development). It is impossible to make money. These can be downloaded and installed directly in official website for free. Windows 7 375-2500 has different prices. It is estimated that there may be a charge for developing a server version if it develops well in the future.