I think the Taliban want the country there, as prior to 911. The tactics they use depends on what can be successful. They would use their “army” to drive out western forces if they could. Since they can’t, thay are turning to other tactics.
You are right, what got them on western radar was giving sanctuary to al Qaida. [I am really a terrible speller and one thing I like about Arabic is that there are multiple spellings for every word and name it seems.] It is really important that the Taliban continue to suffer the loss of their coutry to other Afghanis to show that haboring terrorists is not productive.