Well, that's not entirely true. Modern farming techniques only work in the us because the government heavily subsidizes the agricultural industry, oil and gives farmers access to cheap water. In countries that don't do this, modern farming techniques can actually cause the farmers to go out of business trying to keep up with fertilizer and water. This is actually what's happening in farming communities in south America and India. And then there's the issue with the gm seeds sold to the farmers which wont grow viable seeds on their own, forcing farmers to have to buy seeds each year. Without government subsidies, the current modern farming method isnt sustainable.
But back to msg. Restaurants use msg to cheat the flavor of food. So instead of using actual chicken, beef, vegetable stock, or spices to flavor food, they add msg to "enhance" what little flavor is there. It's not only cheap but you get generically tasting food that has lost all the charm and characteristics of what it was intended to have. I'd rather pay more, eat a little less to have an honestly good tasting dish than shovel vast quanties of cheap crap into my mouth.