> They elect to do that because the crop yields are significantly better and justify the cost.

That is correct. They are so much better ( and I am in awe of that technology) that outside of some niches (depending on the crop) as a farmer you cannot afford not to use them. But now your farmer-timeframe of a few years is up against a 20 year artificial monopoly in the form of a patent. And all your peers are facing the same situation. This isn't a situation where you can just decide to do whatever you want.

You suddenly find yourself dependent on a third party that knows your situation exactly and will try to extract the most amount of value from you - trying to capture your profit while keeping you healthy enough to keep being a customer.

This skews towards the seed supplier.