Resistance to pesticides is expected, just like antibiotic resistance in pathogenic bacteria is a growing issue in health care. There are organisms that have evolved to live in boiling sulfur springs etc., organisms are amazingly resilient and will find a way to survive almost anything. The trick is to manage the resistance.
not when evevery herbicide that has ever been used has resistance issues and for a while they only needed one now they have to go back to using more options but probably still less variation than they needed before. Roundup can be the main and then bring in other when you need it rather than always use the more toxic and expensive other herbicide. This is the problem with the anti-GM folks their option was really go back to using the expensive and more toxic whether its herbicides or insecticides but Gm trait reduce the variation needed but dont remove some variation. Insect protection can be with multiple traits and weed control with a few good herbicides with no threat to production levels (compared to pre GM use). But they don't under it. They also don't get it that Monsanto competitors always wanted farmers to be using their more expensive herbicides and so you wouldn't get any of them suggesting otherwise so since there is no competitor of Monsanto doesn't sell of lot of other herbicides you will get zero support from them and in fact them constantly doubting whether RoundUp was useful while they were panicking their market was diappearing before their eyes. They were fortunate to have the anti-GMs and nature on their side and after 12 years we now need more than just RoundUp and of course Monsanto has options in the wing which again teh competition will hate and try to shoot down while they panic to make their own me-too versions undercover (just like Pioneer did with OGAT). And they did such a great job with that and IMI corn
I walk cornfields all the time. Try it sometime when the corn is silking. You will see insects, and sometimes in amounts that can damage the yield of corn ears for that field. Warning: the pollen will make you itch a little and it can be humid and very warm in the field . Have fun.