Your point would be relevant if there were any substantial number of people who don't get 'high' in some way or another. Yes, weed and alcohol alters your mind. So does caffeine, sugar, Ritalin, antidepressants, spicy food, chocolate, exercise, sex, music, meditation, and sleep. Which drugs and techniques in what quantities work best for you in what quantities is a matter of your own neurochemistry. For example, shrooms and LSD have shown a lot of potential in things like cluster headaches, PTSD, and ironically enough, addiction. If such an enormous burden was removed from your life, wouldn't you feel like you were thinking on a different level? Nobody's perfect, and you might even gain a great deal of insight from being in different states of mind. Not because these states are wholly better than straight edge teetotaling, but because they allow you a different mode of thought, diversifying your perspective somewhat.