They bought DOS yes, I know the story very well as I’m a very few miles from the groups involved.
But word processing, spreadsheet, graphics, WYSIWYG OS adaptations were stolen from Xerox, and later from Apple.
Well actually spreadsheets were Dan Bricklin’s idea when he was at Harvard...remember VisiCalc? Ended up Lotus 1-2-3. PARC didn’t really have any analogous idea, they were more about the GUI and Object Oriented programming.
MS had Multiplan which was boring but they copied 1-2-3 to put on the MAC platform in ‘85 IIRC and then used their hardware sales growth to burn down Lotus. Excel was never the market leader until the early ‘90s.
As for word processors, I really think they did a creditable job there. Remember Apple used to bundle MacWrite with the early Macs, and MS came up with Word for Mac. They read the Mac Programmers standard book end to end and did a fabulous job of adhering to it, and I honestly think that doing that is where they learned to do GUI’s. It showed in everything they did after that.
It was essentially a better version of MacWrite. You could say that came from Xerox since PARC really did come up with that concept and Jobs stole the idea. But MS just worked off the Apple template to come up with Word. It’s not a criticism, that was a great product.
It’s funny. Back in the ‘70s we shared code all the time over the old ARPA net. Nobody thought code was anything worth selling. I remember when Gates wrote the article castigating people for doing that. We all thought he was a jerk for writing it. Stallman got mad and wrote the CopyLeft to try to prevent him from monopolizing the world and realeased GNU to start that ball rolling. And of course Torvaldis went one step further with Linux, again to undermine Bad Bill. But they haven’t been that successful in burning down the MS universe...only Apple.
It’s hard to say what’s “stealing” versus just “competing”, but it’s pretty clear that MS never came up with a paradigm product on their own, they just produced/bought copies and then used platform dominance to make product dominance.
Gates and his family just used Ruling Class connections to make that happen.