>>39216077I feel like it's mostly because of level curve reasons. Yeah Gen 2 had this problem, but beating the Elite 4 is only halfway through the main game, and once you get to Red you're in your 60s-70s, which is common for Pokemon games to end on. No Pokemon game has you ending it's full adventure by levels 80-90, or god forbid 90-100. That's fangame material at that point
The other reason is the workload of course and letting there be an explicit reason for you to visit the second region.
