This blew my mind for a few reasons

Gym Leaders are *supposed* to scale in challenge based on how many badges the trainer has collected. Brock went easy on Red because he only had beginner Pokémon (as you would have). This means if you collected the other 7 badges first, and then challenged brock, he would have had a devastating rock setup including Self Destruct, Stealth Rocks, and Bide.

Also, the fact that the museum is in Pewter city and has a bunch of fossils, that all naturally ties into the whole rock theme, and I never realized this until now