You are right to worry about environmental effects of GMOs. These are often neglected by the general public as they are very complex and sometimes hard to predict and explain. The crops might be good, but one should always ask what the potential consequences might be in the long run and are they reversible.
For the second part, I have to say that it's not GMOs fault the economy works the way it does. Yes, handing over such power to a profit-driven organization will probably not end well, but I don't see this as a reason enough to stop pursuing the dream: abundant and sustainable production of high quality food.
RE: Impact of GMO maze, comprehensive analysis of 21 years of field data