>>58833571Couple reasons
The lore reason is he says he's using his fathers bird Pokemon so we assume his father is originally from Kanto or something like that and the Pidgeys have been passed down in his family for a long time. Falkner and Violet City like a lot of places in Johto are very traditional.
That's just the rationalization GF is giving the player not the real reason though.
The real reason I think is that Hoothoot is a new Pokemon. So in order to make it feel more special they're basically giving it to the player only. I think they want the player to use a Hoothoot against the "old" bird Pokemon.
This is the same basic reason some Johtomon are only in the post game. GF's design back then was based heavily around making certain things feel special. They wanted the player to feel like they were making discoveries of new Pokemon that nobody had ever seen before. That what the whole beginning of the game is about with Birch and Mr. Pokemon.
