>>44665144The worst part is that there was no real reason for them to go either. Easy and Challenge were unlocked upon beating the Champion in White 2 and Black 2 respectively, needing to interact with the other version to unlock the other difficulty.
You couldn't pick them at the start of the game without having experienced it first unless you bought a used copy, which isn't the majority audience.
The only reason they abandoned it was because it was probably a waste of development time tweaking trainer levels, AI, and Elite 4 teams across multiple difficulties. That, or they weren't used enough to warrant being put into future titles.