ReactOS's mere existence doesn't mean it is actually competing in a meaningful way. People use Windows on PCs because it is what is preinstalled from OEMs, not because they made a conscious decision to choose the OS.

https://gs.statcounter.com/os-market-share/desktop/worldwide...

If you want to replace MacOS or Windows dominance, you don't need a better OS. You need an OS that is preinstalled on hardware that people buy.