I would suggest that the Taliban shutting down poppy production was a short term political move, as opposed to an indication that they truly sought to eradicate opium production. Opium has a larger impact on the Afghan economy today than cocaine did on Columbia in its heyday.
I'd further suggest that, even if we wiped out 100% of afghan poppy production for the next three years, there would still be tons and tons of opium. It has a long shelf life, and there are warehouses full of it.
Its also an important store of value, and it works like an alternative currency. Sort of like dollars and gold. Which would you rather be holding if the government was unstable?
The Taliban is largely made up of poorly educated, religious nuts from rural areas. Many of those that can actually read have read nothing other than the Q and religious commentary associated with or relating to the Q. The idea that they will abandon religiously motivated actors in Afghan in favor of helping the US limit terrorism is foolish, in my estimation.