That's an understandable perspective to have! I kind of agree... how do I explain this... okay! The video games would be a circle... that circle has all of the basics to the Pokemon World in it (the people, the pokemon, etc). Everything else like the anime and the manga add to that circle, maybe adding more colors, depth, contrast. BASICALLY, what I think I'm trying to say, is that the games are the base and everything else builds upon it, giving it even more life and perspectives.
I know I'm rambling but I want to give an example! I knew about Drapion from the games, but it wasn't until I saw its debut in the anime did I really start to like it. Things like that can give you new meaning to NPCs, Pokemon, Towns, etc... just like with your perspective with the manga. I understand! (sorry if i bored you, that was long to read)