Well, here are my thoughts:
I am convinced that they will remake Ruby and Sapphire. I'm sure people will buy them, so, why wouldn't they? The question is when and for what console, DS or 3DS. We could use the anime as a reference to guess how long they want Gen V to last. First consider this:
Maybe many of you already know that since Gen III, the anime starts a new season almost at the same time there's a new Generation game released in Japan.
Best Wishes is almost over, the Unova League episodes will begin on Nov 22, and assuming it lasts at least 8 episodes, and a couple more to end Ash's journey in the Unova Region (or maybe more if Team Plasma finally shows up, in the same fashion they did in the game) that means they WILL have to start some filler in February. They wanted to go back to their roots, so, maybe a consolation fruity islands League for Ash after he loses in the Unova Conference? Or maybe the Sinnoh/Johto Battle Frontier.
As for the console, it is possible they could be for 3DS. It has compatibility with DS games, so you should be able to transfer Pokémon from Gen V with no problem, not to mention you will need this in order to complete Gen VI's PokeDex as well. At least at first. It would make sense having remakes step up, FR/LG for GBA, HG/SS for DS, R/S for 3DS. I don't see why would it matter if Hoenn becomes the only region not accesible on the DS, Johto was not accesible on the GBA. However, it wouldn't make much sense to have a remake as the first game for 3DS. GameFreak will probably want to show new features in a whole new game.
So, this is how it could happen:
- The Anime starts a filler in a new random region (or maybe Hoenn), they release RS remakes (maybe DS, maybe 3DS), a year later Gen VI begins, letting Gen V last for another year (kinda), and they keep the same sequence: Gen 3 + Gen 1 remake, Gen 4 + Gen 2 remake and Gen 5 + Gen 3 remake. OR
- The Anime filler is shorter (possibly Battle Frontier since there are only 5 Frontier Brains and Ash doesn't have a Pokémon Coordinator as a companion, which is why Gen V was so short), ending around August 2013, Gen VI games are released for 3DS around September (why September? well, because E, DP, Pt, HGSS and BW were released in September, I'm just guessing). Then a year/year and a half later RS remakes are released for 3DS including Gen VI features. I think this would be worth the wait. This would mean Gen V will only last for 3 years, but I don't see why it shouldn't, after all it's an extension of the DS life-span.