There were definitely console wars back in the day, like with the Sega Genesis and Super Nintendo. (Worth noting that these two platforms tended to have different game selections, with very little overlap; there's even some cases, like with Aladdin and Shadowrun, where both platforms got different games with the same title.)

Even before then, of course, was some competition in the home computer space. Before the IBM PC became dominant, there were other home computers, like the Apple 2, Commodore 64, and even others like the Amiga and (outside the US) the MSX. Many of the titles were ported between them, but not all, and the different ports often have different bugs (as seen, for example, with the Bard's Tale series). The IBM PC eventually won, despite being inferior in many ways; remember how often computers and software would crash back in the DOS/Windows 3.1 days? (One that didn't really end until Windows XP, which is also the first version to have something resembling DRM.) (Back then, one strong reason for using Linux, which was in its infancy back then, was that it simply didn't crash. Windows had more software (remember that WINE, in these days, either didn't exist or was very limited in what it could run), but Linux could run software better without crashing.

Yep, been a lot of changes, a lot of competition falling by the wayside, even when theoretically better. Marketing etc has a lot to answer for.

To a much lesser agree, you could even postulate we have an OS Game War going on, though there is quite a bit of disparity when comparing Linux and MAC to Windows or each other.

Would be nice if true, if devs and stores would pay attention to make it entirely a choice and get Linux to genuinely put pressure on Windows in the mainstream, but sadly isn't.