Windows as a software package would have never been affordable to individuals or local-level orgs in countries like India and Bangladesh (especially in the 2000’s) that are now powerhouses of IT. Same for many SE Asian, Eastern European, African and LatinoAmerican countries as well.
Had the OS been too difficult to pirate, educators and local institutions in these countries would have certainly shifted to Linux and the like. The fact that Windows could be pirated easily is the main factor that led to its ubiquity and allowed it to become a household name. Its rapid popularity in the '00s and early ‘10s cemented its status as the PC operating system. It is probably the same for Microsoft Office as well (it is still a part of many schools’ standard curricula).
The fact that Windows still remains pirateable to this day is perhaps intentional on Microsoft’s part.
I think Windows is successful because it was defacto preinstalled on all computers. Even people in third world countries are buying computers whole, not a basket of parts to assemble.
Also software. You’re not going to assemble a computer, install Linux, and then not be able to run anything on it. You want to run all the software that was built to run on Windows, which was built to run on Windows because it came installed on every computer, etc. (Remember Linux back then really couldn’t run all that much. No office? No games? You’re toast.)