They know that if they actually capture them all they would be left without work. Instead their goal is to say "look they are even bigger than before we need even more funds!!"
On the other hand, if they cought them all, in the long run society will remove the funding, actually leaving us without an "immune-system"
There is a balance to be achieved
The right immune system here would be to legalize the drugs and regulate them, just as we do with ethanol. Then you can remove the funding from war on drugs and related entities. Financing an army of bureaucrats and militants who feast on county's resources and undermine the democracy is not a terminal goal of a society.