But at that point the Talibans had Iran supporting them. Now they have no regime supporting them since the Iranian regime is constantly killed and no neighbor supports them. With 90% of the people not supporting such acts and no external country supporting them with weapons such acts quickly fizzle out into something the police can manage, it never completely disappears though.
Their goal is to kill the leaders until a sensible leader appears. They haven't tested that before, so we will see how it works out.
Installing a puppet regime doesn't work well, but killing them until they put forward a reasonable regime might work.