Let's take Delibird as an example. It can learn a gargantuan 1 move during level up and 39 through TM. It has a BST of 330, shoddy typing, doesn't evolve, and is never used anywhere. It's highest stat is 75, and that's in Speed.
Delibird may be a gimmick Pokemon though. Let's go to another Pokemon now.
I used Beautifly here, but same thing with Dustox. 3-stage evolution line ends in a disappointing 385 BST. It learns more moves, but its shoddy typing gives it a x4 weakness. It's highest stat is below 100, and is an overall disappointment. And Wurmple is worse. A BST of 195 to other Pokemon in the beginning of a 3-stage evolution line's 310. Awful abilities, highest stat is 45, and should never be used.
Why does Game Freak make these Pokemon?