When we realized we're not gonna win in military way after Obama's 130k troop deployment couldn't defeat Taliban of a few thousands fighters in his first term, we began to contact Taliban for negotiation. It was around 2011-2012. It took 10 years for US to pull out troops from Afghan and ended this war. American military industrial complex is just too powerful. If they're not ready for peace, i.e. if they think they haven't made enough $$$ from American tax payers, there won't be peace.