I'm not ready to conclude one way or the other., but keep in mind...
The last Japanese soldiers of WWII didn't come out of their caves until the mid-1970s.
So some people think.
Also keep in mind that Al Qaeda is aligned with such savory terrorist groups as Hamas and Hezbollah -- so there is kind of a fraternal order of terrorists with separate yet connected groups ready to take up where the others leave off.
We'd be foolish to think that the defeat of the Taliban lightens our danger either domestically or abroad.