Keep in mind trip follows what I said. He catches one pokemon at a time and has them all evolve because he has fewer pokemon. Ash caught several pokemon at once, so all the training is spread out, and thus, they don't evolve as quickly. Within the context of the show, Ash is not "a pokemon idiot," seeing as he places top in the pokemon league, meaning he's definitely an above average trainer. For us it seems stupid because the entire game is a big math test, so statistically, evolving really is the way to get better. Within the anime though, those rules don't apply, so it's not fair to judge Ash by the standards of competitive battling. You'd be a horrible person to actually use a life orb on a pokemon if they existed.
I suggest looking at this: http://pokemondb.net/pokebase/meta/5004/anime-faq-for-anyone-who-wants-it
And of course, let's ignore all his pokemon that already have evolve and just pretend they didn't.../sarcasm