>>20975497Pidgeot was a rare exception of something that HAD to go because Ash could fly around on it, which would negate the filler mon eps and daily team rocket attacks that the show needs to run for as long as it does. Otherwise he'd just fly from Gym to Gym and he'd have all the badges within 10 to 20 episodes, and then they'd be fucked because they need to drag the season on for 4 years or more until the next game is out to give them more opponents.
That's why they made sure he only caught small bird mons from that point on, so he'd still keep walking everywhere.
Pidgeot's never coming back. It's not conicidence it left around the time they realized the show was gonna run forever.