That's all perfectly true until something wipes out your monoculture, then it is a bit of a problem.
Too many eggs in a single basket is always a dangerous strategy, it will work perfectly for a long time and then one day you lose all your eggs. That's only a matter of time.
Could you please point out examples where GMO crops have been wiped out because of monoculture? I have yet to see any examples and yet people continue to use that argument. (Serious question, I would love to see more info on this issue!)
That is exactly the problem, this will work until it fails. Score to date: 0.
But we do have examples of such crop failures due to monocultures in 'regular' agriculture. All we have with regards to a GMO problem is speculation and a hope that it will never happen.
The only instance that I'm familiar with that shows a little bit of what the risks are is a south african incident where farmers lost up to 80% of their GMO corn crops.
Too many eggs in a single basket is always a dangerous strategy, it will work perfectly for a long time and then one day you lose all your eggs. That's only a matter of time.