Billy wrote:

It is sufficient to cross pollinate existing cultivars with GMO pollen,
and it is destroyed. Once Monsanto's gene is in the cultivar, it belongs
to Monsanto.

This is a point where current law needs to catch up but it's not an
easily resolved issue.

On the one hand seed stock from Monsanto can be sold with the caveat
that the plants be harvested before they bloom. And reasonable efforts
can be made to keep cross polination from happening.

On the other hand if a farmer took no action to encourage pollination
bees will be bees and it happens.

Apple patents can be enforced because apple trees don't breed true. The
only way to get a specific cultivar is to graft a branch from an
existing tree. The more widely pollen spreads the less enforcible a
patent is. The problem is this makes the investment by Monsanto less
profitable so they have less incentive to make the next development in
crop changes.