The guy is just a founder of a company who sells a piece of crap os and some other software.
If Windows is 'a piece of crap os' what do you call a 'competing' os that has failed to usurp it in its primary market place?
"In the area of desktop and laptop computers, Microsoft Windows is the most commonly installed OS, at approximately between 77% and 87.8% globally. Apple's macOS accounts for approximately 9.6–13%, Google's Chrome OS is up to 6% (in the US) and other Linux distributions are at around 2%"
A 'piece of crap' has nearly 90% of the market, Linux has 8%. The job of an OS is to provide services and it's clear that Windows is providing services to far, far, far more people than Linux. Measure by what it achieves not what your friends in the ivory tower think.
Even in the server market Windows still has a very healthy share and is continuing to give Linux a run for its money despite Linux being (sort of) free and Windows very much not.
It's only really the mobile market where Windows could be said to have failed.
There are many, many things wrong with Windows. It gets up my nose every day (that and Visual Studio) and Linux is technically superior. But calling Windows 'a piece of crap' is silly and demonstrably wrong. Operating systems and software exist to do a job and it's obvious that Windows and its software stack has been doing the job well enough to remain a dominant force.