Question

Do all the trainers have level 60 Pokemon after completing the story in Pokemon B/W?

Comments

technically no, all battle areas, like the battle subway, have lv. 50 pokemon

Answer 1

The ones on the roadsides do. It’s completely normal for post-game NPC trainers to have a sudden jump in level.

Comments

He/she/it's asking whether ALL of them have high levels. This doesn't answer the question.