1. US certainly experienced defeat in Vietnam but a setback in this expedition was inconsequential to the grand scheme of things in relation to the Cold War which ended in the favor of the US by 1991. FYI:
https://defence.pk/pdf/threads/history-of-american-wars.538912/
2. Iraq is recovering.
3. American expedition was restricted to 'regime-change' in Libya. Its aftermath does not matter.
4. American expedition in Afghanistan has not ended yet. However, they reduced Al-Qaeda Network to insignificant levels in Afpak region [primary objective] and they continue to punish Taliban for their lack of political foresight and acumen. Taliban-based sources have openly expressed their desire to negotiate an end-game with the US recently. Irrespective of bluster and noise in media,
US continue to call the shots in Afpak region.
Now, if some members were expecting Hollywood-style idealistic/utopian outcomes in real-life forays then they will be disappointed. There are some 'local/regional realities' that US can never address with its politco-conventional interventions - no foreign entity can.
US can erase Afghanistan from existence with its firepower [if desired] but it cannot transform Afghanistan into a democratic utopia [Afghan society is too tribal and fragmented for its own good].