From where did the US go wrong in Afghanistan?

Finally, the United States realized there is no military solution in Afghanistan, although the realization takes 20 years and still complete withdrawal has to witness. What they've achieved in Afghanistan after spending almost two decades? not achieved a single desired result at least it was not surprising as media told us, the approach the US has made right after the 9/11 incident based on fallacious. 

After Soviet dissolution, Afghanistan has fallen into political isolation where the third party has taken full advantage, as a result, the country emerged as a war zone. The 9/11 incident bring that opportunity to re-engage, or re-align with the international thinking on Afghanistan, and bring the end of political isolation that existed before that attack.

Washington's approach right from the beginning was erroneous without even visualize the consequences before the US has implemented an offensive strategy through military intervention. They've committed numerous blunders which were discussed below.

• Soon after the 9/11 incident, the US sought a military solution, the Bush administration announced war against the Taliban and carried out deadly airstrikes inside Afghanistan. This was the first violent move from their side and it was going up to high intensity as the retaliation comes from the opponent force.  

• During the first interaction between Musharraf and Bush, the first thing Pakistan told at the summit level to President Bush was that there is no military solution in Afghanistan, keep hearing from our political leaders now, at that time Pakistan had proposed the same idea to a political solution but they refused to adopt it.
• Thrown a de-facto government by forced whatever the legitimacy or illegitimacy of Taliban regime it should be transit to a political strategy to finds a solution which can bring all the stakeholders on board and perceive a long-lasting solution. 
• Next they did a mistake when they dominating the military presence in the beginning years, that was the time to seek an inclusive political solution when the Taliban also seek a political engagement. However, the US keeps imposing a military solution and this went on since Obama took over.
• In December 2009 President Obama delivered his famous speech on a new strategy for Afghanistan and he said, 'We are going to transit from a military solution to a political solution.' But, the first step in the operationalization of that strategy was the military surge, subsequently, when the time came for dialogue with the Taliban it was delayed right from 2011. Since we see a very serious engagement.
• Then a Doha peace process took shape, but again it was not sincerely pursued because some voices came inside the US against the Doha agreement and the Afghan government didn't want this either.