美国越战也没打赢,---Yes, You are right.
But USA actually controlled the War if they didnt fire the fight across the Line which China Draw. And yes, they were not dare to across the line because they realize Chinese words must to be listened and treat it serious from 韩战 lesson learnt, they can not be bullied. But 韩战 they can not control the War, actually they are losser. This is one point of the differents.
输得比韩战还惨。---Maybe not, you can check how much they put in these different 2 wars, and how much they lost from these 2 wars, you will know 输得比韩战还惨 is totally not correct。
Sorry i dont have chinese software here to type chinese.