Game Freak had different plans for this generation. However, that would be suggesting that GF has a "tradition" going, which isn't entirely accurate.
Ruby and Sapphire were introduced, then FireRed and LeafGreen, THEN Emerald.
For Gen 4, Diamond and Pearl were released, then Platinum, THEN HeartGold and SoulSilver.
While the issue isn't about remakes, it shows that Game Freak doesn't have a set tradition that they have made official. They've never said that we would get remakes for every generation, or that they would always make a 3rd version of the main games. People just assumed they would do the same old thing they did before, but I'm glad to see them change things up a bit.