As much as I would love RSE remakes, I do agree that any reason to create RSE remakes is as good a reason to make FRLG remakes.
The truth is that remakes of FRLG would make GF piles of money, and we know that's they're main focus: to make games that are profitable. I said this in the Yellow remake thread - there are a large amount of people who played only the first games and are of the opinion that Pokemon "turned crap" after Gen I (which obviously isn't true). This means that even those who are no longer fans of the franchise will be more inclined to pick up these games purely out of nostalgia. It could even be a deciding factor for those who were unsure about purchasing a 3DS (i.e. it might persuade them to buy one).
I actually think that remakes of FRLG would actually sell better than remakes of RSE.
That being said, I would rather have RSE remakes. MiTjA does make a good point though. If FRLG appear on the virtual console, I'd expect RSE to be there too.