I just found this interesting - especially the last paragraph.

https://www.theguardian.com/world/2011/sep/27/10-myths-about-afghanistan

Guys, I just can't talk about the Middle East in terms of last month or last year or Obama or Bush or Bush or, for that mater, Bush. I guess I need to define my terms.

The boundaries in the Middle East are largely an invention of Western convenience. Multi-national corporations make sport of our patriotic sensibilities as they create boundary-blurring trade pacts that undercut our workers in the name of "free trade".  
Anyhow, this is the "reason" Obama didn't, and Trump won't and the POTUS doesn't matter because the POTUS doesn't call the shots.
If you don't already know that the oil cartels are in charge, you haven't been paying attention.

https://iakal.wordpress.com/2016/07/01/the-afghan-oil-pipeline-and-the-us-negotiations-with-the-taliban/
  
http://www.marketwatch.com/story/halliburton-dubai-move-revives-foreign-tax-controversy

Patriots all.