1. This is a exclusive problem for the US. A County with a working justice system would acknowledge biological gene mobility and the natural reproduction cycle. That means farmers will be able to grow plants out of their own seeds as well as cross the mutants with relatives to keep the benefits alongside biodiversity. This is of course no business model but open funded research could do it as well.

2. Most scientists have a strong opinion against herbicide resistance (like round-up, round-up-ready). These genes are very quickly found in other plants do to gene transfer so it's only a short short sighted solution.

PS: Glyphosate is the best herbicide we know. Your argument is valid for all herbicides but with roundup the least.