The North Vietnamese and Viet Cong captured huge amounts of war material when the US departed Vietnam in April 1975 during the Republican administration of Gerald R. Ford. This is nothing new.
One might also remember the Afghanistan engagement began in 2001 under the George W. Bush presidency. It lasted 20 years. Perhaps if Mr. Bush had a plan when he went in, it wouldn’t have been the longest war in American history.
Even better, perhaps Presidents Bush and Johnson should have heeded George Washington’s warning to future generations about getting involved in foreign entanglements. Both Vietnam and Afghanistan cost the nation the blood of its soldiers and trillions of dollars. The end result? Nothing for the people of the United States. In fact, today we export American jobs to Vietnamese factories.
Being defeated sucks, but we could stay another hundred years and it wouldn’t matter. The people there are ungovernable. We should have a vote and those who want us to stay should be forced to serve there, or their children and grandchildren until victory. And it should be pay as you go with those in favor of staying funding it with a special tax on their income and assets until we achieve “victory”.
The main benefits we accrued from those of us who fought were that our allies and adversaries saw us fight effectively for another people for ten hard years. The old "paper tiger" smear was visibly disproven and over the long haul, led to the fall of communism and the Soviet Union/Warsaw Pact.
I take it you were not able to fight?