Gen 1/2 -> 3 transferring was never made because there was never a way for GB/GBC carts to communicate with GBA ones. Gen 3 -> 4 worked because old style DS units had the dual slots (1 for DS cards, 1 for GBA carts) and subsequent generations have internet/wifi based trading and compatibility between DS and 3DS cards and systems.
Additionally, how pokemon data was compiled and set up was radically overhauled between generations 2 and 3. Even if there was some sort of fantastic way to move RBY/GSC data to an RSE cart or beyond, the newer games likely wouldn't be able to make sense of how the older style pokemon were supposed to function. FR/LG may be Gen 1 games in terms of being in Kanto and playing like RBY, but they were build on the structure of Gen 3, with all the changes to pokemon data that Gen 3 brought about.
EDIT: and now I realize this question is like a year old. Whoops.