Ok, let us compare this to a different platform, the
Gameboy.
To a layman, it may seem that there is only one kind of gameboy (perhaps with different colors), but of course that's not really the case. Since its launch back in 1989, there have been numerous different products in the gameboy line. For example, there's the Gameboy Pocket, which runs on different hardware (and looks markedly different) than the traditional Gameboy. Aside from that, there are peripherals and accessories (such as the Link Cable) that may be present on some Gameboy systems, but absent on others. Finally, there are some third-party products that Nintendo doesn't approve of but that nevertheless work with the Gameboy, such as the Gamebooster.
So the point is that there is not a single set of hardware (or software) that can be called "Gameboy". Now
what makes this all the same platform? Obviously, the answer is COMPATIBILITY. A Gameboy cartridge is designed to run on any Gameboy, because it's the same platform.
Then we have the
Gameboy Color. To a layman this may be "just a gameboy" but we know that it's really not the same thing. Now, the GBC is built on the same technical specifications as the GB, built upon the original gameboy's design, and in the same family. However, it has more memory and a different brand of CPU that's also faster, although it uses the same instruction set. Overall, the GBC is a different
plaftform (and we do
categorize it separately) because of COMPATIBILITY. Simply put, GBC cartridges don't work on a GB.
Since the architecture is the same, the designers were nice enough to implement backwards compatibility, meaning that GB cartridges work fine on a GBC (natively, with no emulator). Of course, backwards compatibility is rarely 100% - there are in fact a handful of GB games that don't work on a GBC, because they're different platforms. Also, eventually Nintendo stopped supporting backwards compatibility, in that the Gameboy Micro doesn't support GB cartridges any more, but only GBA carts. Aside from that, "hybrid" cartridges exist that work on both GB and GBC. But overall, a GB cart is not a GBC cart.
Same family, different platforms.
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So, are we going to ignore twenty years of development in claiming that these are all the same platform? Despite the fact that old GB carts don't actually work on the GB Micro, and GBM carts clearly don't work on a GB either? Are we going to take the layman's view that all of these are "just a gameboy"? Obviously not.
Then why on earth should we do that to DOS and Windows? Clearly DOS and Windows are two very different platforms, running on very different hardware; and clearly DOS games don't run on Windows (except in an emulator) nor vice versa. Are we seriously going to pretend we're layman who can't tell the difference? That really doesn't make sense.
(Oh, and Doom? Doom has ports for multiple platforms, including DOS, Windows, SNES and PSX, and several others. That's nothing special, we have many games
that run on multiple platforms. Nobody is claiming that a SNES is the same platform as a Gameboy just because you can play MK3 on both, after all...)
