>>47778479>Why?The actual reason is because Gen 2 just treated new Pokemon different from all later games. In Gen 1, the baseline was Gen 1 (obviously). In Gen 2 the baseline is still Gen 1 with the new Pokemon either complimenting the older Pokemon by being more com mons (Hoothoot, Sentret, etc) that excite new players or hiding them throughout the game. Wobbuffett was in only one location, etc. Most Gen 2 mons are like that in the game because they were being considered special. The reason why there are new Pokemon exclusive to the postgame where they won't be useful in main game anymore is twofold: because the act of finding and acquiring a new Pokemon is a reward for the postgame and because they expected anyone who honestly wanted to use these new mons to be playing competitively. By the time of Gen 2's release, GF were explicitly appealing to competitive so they probably didn't think stuff like not letting the main game use Misdreavus or Houndour because you could use them competitively.
It's pretty clear that GF's take of "Gen 1 mons with Gen 2 mons supplementing the Pokemon pool or and serving as 100% completion bonuses more than anything" didn't work out because by Gen 3 they had moved to the now more standard "Gen 3 with other Gens as supplement" strategy and only kept a couple non-legendaries for the postgame.
I think plenty of people don't actually think about it that much so they just think GF are retards because they don't let you use Houndour until Kanto. It IS kinda retarded but if you think about it from their perspective it makes some sense. It's not like they knew how the formula would work right from the first sequel. Also with Gen 2 being a direct sequel to Gen 1 you could make the case that's another big reason why it's Gen 1 + friends.