Well, we've had Atari collections on Nintendo platforms, so I think the problem is that Atari/Nintendo don't really care to go for it. YOu probably also have to charge way less because the difference in games can between Atari and NES games can easily eclipse... well, almost the entire industry from that point forward. NES gave the ability to make longer, meaty games that were literally impossible on the Atari.
I realized something: even if Nintendo can easily do this for free, it may be a necessary evil to coerce third parties into getting their stuff supported here. Afterall the promise of more money, even from people who already bought it, definitely makes it a much more appealing prospect than just giving it all to us again for free.