In issue #71, I wrote a feature about DOS gaming, and I tried to address some of the reasons that it's a neglected retro platform. As I said then, I think it comes down to a lack of attachment to a memorable image. Most PC owners were on an upgrade treadmill for one thing. The machines themselves were also a bit fiddly to operate, and I can see why the consoles are a bit more attractive to collect for.
The platform itself is great, however. Generally, it lags behind dedicated home computers in the graphics and sound department until the VGA era. However, I don't understand the argument that it wasn't worth bothering with until that point, particularly when we're discussing it on a retro forum. Even when it lagged behind technically, DOS still enjoyed plenty of great releases. I'm not going to link directly from the forum, but google for DOS abanonware and see how much stuff there was. Windows PCs quickly got way ahead of the Playstation, and I'd say that it was still a platform worth following. What technical advantages does the MD have over the SNES? Is the MD rubbish?
By the time the 386 was common, such a machine with a soundcard was about the best machine you could get if you were a fan of simulations, adventure games, etc. If you were into shooters and platform games you'd have to be a bit mad not to be running a SNES or MD. I'd agree that the Amiga remained the most well-rounded gaming machine of that time, and unfortunately, you needed to be able to invest about 1,200-1,500 quid into a PC.
Personally, as a bottom feeder, the PC has always been good to me. I've never had much money as an adult, and when I started again with computers, I picked up a 386 for about 200 quid. Since then, I've upgraded it like Trigger's broom in Only Fools and Horses. Another way that I got into PC gaming was via emulation.