mcnichoj: They would have to make a new port. The whole point of these releases for Konami was to just make some money, not actually have to do any work.
That's exactly what they did with Metal Gear. It's the same release that was included in the HD Collections by BluePoint games, not the original DOS version of the game which was pretty janky. Had they included that, considering Metal Gear has always been oficially present on the PC that way, it would make sense to re-release Metal Gear but not Metal Gear 2 Solid Snake.
But considering they opted to reconvert it from the HD Collection release, then it's totally pointless not to do the same with Metal Gear 2 Solid Snake, which is obviously the best 2D Metal Gear game by far, even better than most of the Metal Gear Solid titles (in fact, the first Metal Gear Solid events are largely based on those of Metal Gear 2 Solid Snake).