I think Gen 3 remakes are still going to happen, because Hoenn is currently the only region that can't be played on the DS/3DS and also the only region that isn't visitable with the "modern" battle engine (ie. Physical/Special split).
There's also the fact that Hoenn came out during the series' first major downturn in popularity; The kids who'd grown up with Gen 1 & 2 were in that pubescent phase where they're trying so hard to look "adult" that they'd never be caught dead playing Pokemon. By the time DP came out, Pokemon found its renaissance on the waves of nostalgia, and now a remake of Hoenn would likely find a larger audience than the original release (not to say the original release did poorly; it was actually the most sold game on the GBA. but Pokemon is more widely popular now than it was during that period, for sure).
After Gen 3, though, then I think remakes will be over. They might do Kanto again just to get the original gameworlds into 3D, but at the point where we move into the "modern" era (with DP) it becomes kind of redundant to remake the games when there would be little to update.
