After the Soviets withdrew, Najibullah's regime held out longer than anybody expected, and the civil war that erupted afterward was also worse than anyone had feared.  Some of the factors that contributed to that, and to the subsequent rise of the Taliban, would not be repeated if the international troops were to leave today.  But there are a whole host of new and different factors that would affect the outcome, some for the better and others for the worse.

In short, I have absolutely no idea.