This is a common misconception - that some GMO plant can suddenly take over the whole area or something. This doesn't work this way - no cultivated plant is better adapted to the local biosphere than the local wild plants (we call them "weeds"). This is precisely why farmers need to put a lot of effort into weeding to keep their plants cultivated. Leave a nicely cultivated orchard for a decade, and it will all turn back into wilderness.
Many people thing farming is just like gardening, just on larger scale. It's not - farmers plan soil rotation for decades. And as already explained, *any* crops currently in use is GMO and has been for thousands of years. The fact that Greenpeace lobbied calling GMO developed after 1980 "the GMO" is just a manipulation.
Regarding soil etc I can only recommend Talking Biotech podcast as they discuss it all the time http://www.talkingbiotechpodcast.com/
What you are talking about is monocultures and they're certainly bad, but they have nothing to do with GMO. If anything, modern GMO crops reduce land usage *and* reduce pesticide usage. In case of Bt brinjal in Bangladesh it was some crazy numbers - like 80% reduction in herbicide usage and 50% increase in harvest.
Please note that I did not disagree with any of your points - it's just that the fact that they're using GMO crops is orthogonal to the fact what they're growing is a monoculture.
@kravietz @alrs @feld That decade timeframe is part of the problem. Look at all the government subsidized commodity farms in the mid-west growing GMO crops. It takes at least 5 years for the soil to recover and have the ability to produce something that’s not corn or soy.