I don't know. I mean there are two kinds of people, people who will buy a game for an old system, and those who won't.
For those who won't, emulators have been around for 10 years already, as well as CDR copies on e-bay and bittorrents. Now the industry is just finally adding "legal" ways to do what everyone's been doing for a long time anyway.
These people have no desire to pick up an old system and old games. If they can play the entire NES library on their X-Box, PSP, or PC, it's good for reminiscing.
But then there's those who do. Anyone who's going to buy old carts for old systems isn't a reminiscer, their a collector, and collecting is different, because it requires ownership of an original, physical item. That's why people will still pay 100$ for a SegaCD RPG even though you could download it for free.
There are other reasons someone buys originals. Some people can't afford new consoles. They still have an old nintendo or sega, and that's all they have for their new kid to play. Or a grandchild or nephew who visits occasionally. For those people, they are limited to 5$ games. They have the system because it's cheap, and they only buy games because they're cheap.
There are also the "hardcore" gamers who know that original games on original hardware with original controllers play differently that emulated games. Emulated timing just isn't quite the same, and high-resolution superscaling of original low-resolution output doesn't produce the same necessary blurring or scan-line effects. And most of all, no one has managed to create a controller that doesn't suck since the Saturn. You can't play control-intensive games (fighters, shooters, etc) on new style controllers. The D-Pads and button-layouts suck. You can still buy high quality arcade sticks for 100$ for new consoles, but that's a bit steep for me.
And in that case, the fact that old games are mostly cheap these days helps out. I'll easily pay 5 or 10$ just to get a better gameplay experience on the original hardware than on a free emulator.
One side effect is that it creates a larger gap between mint and loose games. Where a loose game might sell for less than 5$, complete it could go for 50$, and factory sealed 200$. The later being limited to the collectors.
Me personally, I buy 100$ games minty complete for the collection aspect. I buy 5$-40$ games for the better gameplay experience (price depends on how good it is). And I use emulation exclusively to "try before you buy". If I know it's a classic I'm going to keep forever, I'll look for complete, but will accept loose if the price difference is high. If I just want to play it once, or give it an extended try, then loose is just fine.