Your statement mostly applies to the AT/286 era and beyond. Very early PCs were not clones but rather MS DOS compatible which is different (BIOS was not compatible). Even when true clones appeared with compatible BIOS system designers like Tandy would try to innovate with things like "Tandy Graphics and Sound" which are sort of PC Jr graphics but not quite, etc. Having the ability to emulate the older machines is a boon to gamers.
However, I have no idea why anyone would want to emulate Cyrix chips or later PCs other than out of curiosity. A lot on this list does seem superfluous.
The collection of supported machines does seem to concentrate mostly on the older systems. The newer ones seem to be examples of the interesting quirks that were in place in the later days -- ATI's WinBIOS for example, or Compaq's machines which used a stripped down copy of Windows 3.1 as the bios utility. Gut feeling for the newer systems is mostly to couple with the newer video cards on the list -- the S3 Trio64 and the 3dfx VooDoo.
>However, I have no idea why anyone would want to emulate Cyrix chips or later PCs other than out of curiosity. A lot on this list does seem superfluous.
Gaming, mostly. A lot of computer games from back then simply will not run on modern machines. Even after things fell into place with DirectX/OpenGL, Windows is such a complex system that keeping all those millions of plates spinning at once is simply impossible
There's games today that I can't run from the last 15 years alone, like Westwood Studios Command & Conquer series. The company is defunct, and the buyer (EA) lost the source code over a decade ago, if you believe the rumors. There's simply no other way to RUN the game past Windows 7 (EA no longer bothers patching it to work on newer systems with their re-releases)
The only alternative is really to simply buy the older hardware, which is becoming increasingly scarce and difficult to maintain (why would we keep these 30 year old Video card drivers says someone at AMD, before rm -rf'ing them off the FTP for instance?)
While PCem is a more accurate emulator (it's very close to cycle-accurate even), I keep an installation of Windows 3.1 on DosBox around to play really old games. It works for 16-bit games like the original SimTower.
Maybe one day I'll get adventurous and see if Windows 98 will run on DosBox.
However, I have no idea why anyone would want to emulate Cyrix chips or later PCs other than out of curiosity. A lot on this list does seem superfluous.