The other question you should ask yourself is: How we all end up with x86?
The other thing is localisation which happened all over the world with MS softwares, when no other companies bothered to translate the apps to non english speaking users. Before localized version not many secretaries were capable to work with wordprocessor not even mentioning spreadsheets.
As previously mentioned ignorance of the other OS developers let it happen, and marketing of MS and additionally good user experience helped a lot. When Windows 3.1 appeared PCs were already everywhere - doing accounting and wordprocessing - and that time Mac was really overpriced and to prorietary to be considered as an alternative. Even with lackluster performance and buggy drivers usefulness of WYSIWYG was enormous for the masses, and even secretaries with better-than-average DOS Word knowledge - I mean knowing shortcut keys to copy-paste - changed to slower GUI due to company requirement/printer compatibility or both.
The other question you should ask yourself is: How we all end up with x86?
Back in the Motorola 68000 days, intel was inferior in every aspects, smaller set of registers and all of the tied to a specific function, limited bus size, and probably a couple more, but still market penetration was higher due to the big names behind it. That times three companies - probably more, but not on worldwide scale - used Motorola successfully:
Apple, Atari (ST), and Commodore, and only Apple survived the decline of 68000 and not w/o huge shrink, the other two died probably because everyone outside the actual users counted them as gaming only platforms.
If you go back the times when ZX Spectrum fought with Commodore 64 then there was a level battlefield at least. Spectrum had a more powerful CPU, but C64 had video and sound advantage so both gathered followers as today the same goes with the consoles, and there was no need for interoperability.
But today with corporates communicating around the world you need a common language and until web based applications starts to evolve into something really useful - from corporate standpoint - then monopoly of MS would stay, because even Linux apps has to mimick Office to be considered viable, instead of creating sometying revolutionary.
So we got stuck with an inferior OS on an inferior platform because of marketing powerplay or common inertia or plain laziness or lack of confidence in upcoming companies but probably all together. Heritage of the original x86 is still architecture is still depressing, but thanks to clever engineering and compilers they overcome most of the limitations.(Probably if PowerPC CPU had had as much capital behind E&D as x86 then the performance crown should belonged to it rather than the Intel stuff, and even MS Windows would run on it - however they dropped Alpha but that is an other story)
YMMW.
George