Just because something's never been done before doesn't mean it can't now (BW2 being the most notable example in this series). We're reaching a point now where several games are becoming obsolete in the same generation. RSE and FRLG became obsolete on the 3DS, and next gen DPPt, HGSS, and BW will also join that list. So I think it's possible we could see a Kanto remake soon. As for remaking Emerald, they've pretty much exhausted everything they can plot wise at this point, but gameplay wise we really haven't gotten the Emerald experience out of ORAS, they barely included any of the upgraded features from Emerald in the same way that HGSS did with Crystal. (in fact arguably they didn't include anything from Emerald if you don't count the Delta Episode as Emerald content). Really though, I think things line up better for ORAS2 than Delta Emerald though, most of the missing Emerald content is shown to take place after ORAS in that game's universe, and they could do new things with Hoenn like a dex expansion and more changes to the region. But I'm not expecting anything else Hoenn related anytime soon.
I never said it was impossible, just that it was unlikely. I prefaced my post saying I was exclusively using trends to predict, and one generation out of 5 (not counting the current obviously since it's not done) doesn't completely invalidate my observations. As for DPPt, HGSS, and BW becoming obsolete.. I must admit I'm confused. Are you suggesting that the next game will be exclusive to some new system? That would be the only way they would truly become obsolete. Currently, all are playable on the 3DS and can migrate pokémon up to the current games so long as you can complete the gen migration chain (DPPtHGSS ->BW, B2W2).
As for a Kanto remake, I'm not saying it is definitely not going to happen. An outcry from people who wish to experience the nostaliga for a fourth time could win out and they could get made. I say fourth because if you bought an initial game from gen 1 (Red or Blue), the follow-up (Yellow), and one of the remakes (FireRed or LeafGreen) then you have already be crowned Kanto Champion 3 times. If you are like me and own every version and have beat it, the you are a 5 time Kanto Champion. I suppose if you want to do it a 4th or 5th time in 3D you could I suppose, I just don't see what another remake of Red and Blue(Green) would really bring to the table. We already have megas for the starters (2 for Charizard) and 2 Mega Mewtwo. ORAS brought us Primals and other megas... but seeing as Mewtwo is the only big legendary I don't see these games bringing in anything plot related like Primal Reversion. Instead we'd just get some more megas, but any new game could do that. Now, a couple years down the road when we get what ever system with follow the 3DS I think it would be more appropriate. There may be some new dynamic or system functionality that would make a return to Kanto a meaningful experience rather than just some echo of former glory.
As for a sequel to ORAS, I don't ever expect that, and I say that with 100% certainty. Sure, the Delta Episode was no Emerald. I agree with that. However, I disagree that Emerald is a "sequel" with events that take place after the main story of RuSa. The only aspect of Emerald that took place after the events of the main plot was the Battle Frontier. Emerald was RuSa1.5 essentially. Up until the end of the game, it was essentially a retelling of the same Magma VS Aqua story just without one of the teams helping you out. Sure, a Gym Leader was shuffled to Champion and the Champion went to live in a cave.. however, I doubt this would be enough of a premise for an ORAS2. In fact, I think it would be a terrible idea. Unless they introduce some new gimmick like Primal Reversion there wouldn't be any reason to revisit the region. In sequel terms, Groudon/Kyogre and Rayquaza have already been captured. I know B2W2 allowed you to capture Kyurem even though it had already been captured in BW potentially, however in BW Kyurem had essentially no plot associated with it. Instead it just some off handed comments by NPCs. Rayquaza, which was the focus of Emerald, has been resolved in the ORAS universe with a clear story arch. It is now Brendan's/May's pokémon. It would be weird for it to suddenly be free again as a plot point. Additionally, Groudon/Kyogre is also Brendan's/May's... so for there to be another weather arch (Groudon VS Kyogre with Rayquaza stepping in) Brenden/May would have to allow thier Groudon/Kyogre to go on a rampage and then release thier Rayquaza for some new main character to recapture. That seems like a reach. Also, for those who say that Omega Ruby 2 could let people get Kyogre and Alpha Sapphire 2 could let people get Groudon I say this.. if you want the opposite version guy, buy/trade someone with the opposite version.
Anyway, to bring it back to my original post, I still think X2Y2 is the most viable option. If it doesn't happen, then I don't understand why Zygarde would have 2 hidden signature moves (Thousand Arrows and Thousand Waves).