Agreed on the trademark, or in actuality what will become plant patents. Plant patents are good for 20 years (in the US) and that is what is used to protect strains of new roses, orchids, and other prize plants from being cloned and sold w/o royalties being paid to the owner of the patents. I am sure that Dave Watson is salivating, sitting on his metric ton of Cannabis seeds, and will patent all his strains. Though you can still clone them if you get a live cutting, and sporadic S1 seeds will be created from herms. They have inadvertently generated a future of herms by creating and selling so many fem seeds.
I do not believe that the demise of land race strains is centuries out though. It is a few decades out at most at the current rate. For multiple reasons. Juan Valdez is not the guy that is growing all that much weed any more. It has become much more large scale than that, and the growers are being sold modern seeds strains on all levels. Also the black market is greatly decreasing as North/Central American and European countries legalize weed. Legal weed in the western states has already resulted in many growers in places like Sinaloa, Mexico to stop growing Cannabis. Though they had few, if any land races of Cannabis there to preserve. In places like Sinaloa, they had/have mostly auto, feminized and modern Amsterdam strains. Morocco is about half Pakistan strains now, and half original Morocco strains. The Morocco strain grows are getting smaller and smaller every year.