>>54898194After that... maybe they forgot or lost interest in doing this. Who knows? Game Freak sometimes does things that make no sense, like how Colress was perfect for Mega Evolution research but all he got during Gen 6 was a small mention-- and then he did a bunch of things in Gen 7.
And there is Shauna who could've had a Lopunny alongside her Delcatty but didn't. Then ORAS had Mega Lopunny but it wasn't part of May's final team. Again, things that just make no sense.