A few points:
i. while you can say that Ash didn't evolve his Pokemon, he did train with them
ii. the anime focuses on the fact that Pokemon don't need to evolve in order to achieve more; however, this is impossible in the games due to everything being determined by base stats - even with perfect IVs, a Squirtle is no match for a Typhlosion
iii. when you get to Red after climbing that huge mountain, how are you going to feel when the champion's Pokemon are easier to beat than the Golbats you had to swat away to get to him? If Red had a Bulbasaur and a Squirtle, he'd be easily beaten
iv. it's actually not that commonly accepted that Red & Ash are the same person, because Red and Ash are different a lot of other ways, the main one being that Ash isn't Kanto Champion, and his journey didn't end in Kanto