Something is missing in that story. Afghanistan isn't a great location for any sort of agriculture: it lacks the reliable rainfall and flat plains needed for optimal cereal cultivation. And as a landlocked country it's impossible to export large volumes of grain. Most of what they grow has always been for domestic consumption.
It is precisely because of those obstacles that opium poppies are one of the few practical cash crops. One motorcycle can carry the refined output of an entire farm.
One might consider that it would give something for these farmers to subsist on that didn't enrich the Taliban. With that issue settled and stable, you could make inroads elsewhere without inadvertently filling up the enemy's coffers.
It is precisely because of those obstacles that opium poppies are one of the few practical cash crops. One motorcycle can carry the refined output of an entire farm.
https://www.nbcnews.com/id/wbna24489703