The difference with Microsoft is the monopolistic power they got because IBM adopted their OS for the IBM PC.
It is a complicated story, and there are a lot of questionable anecdotes about it, such as how Gary Kilmer, who wrote CP/M was out flying when IBM execs came around to see him, and the execs were miffed enough to go with Microsoft. Or the story that Bill Gates' Mom was on some charitable committee and heard from an IBM exec on the same committee that IBM was looking for an OS.
The IBM PC was an overpriced, slipshod piece of hardware even by the standards of the time. Maybe IBM just wanted something to connect to their mainframes as they were focussed on that end of the Computer business. However, because it had the letters IBM on it, laymen who didn't know any better bought it, and it had MS-DOS on it. (Which wasn't particularly good.) When the clone makers came out, IBM didn't stop them, and they were allowed to use MS-DOS. This became the standard. When people came out with Apps like WordPerfect that weren't MS, MS was able to 'enhance' MS-DOS to make the competitive apps not work anymore.
The result was to hurt the nascent industry in my opinion. (I know, shakeouts and oligopolies were inevitable, but I think MS got too powerful too soon with too little effort.) Microsoft was going to capture the server market too, at least for small networks, but fortunately, there were enough knowledgeable technies working in the back offices of those small business to subvert their PHBs and put linux and/or FreeBSD in and escape being monopolized by Microsoft.
I shudder to think where we'd be now if MS had captured the server market.