[pfannkuchen]

Destabilized nations are good if you are a nearby nation wanting to expand and you expect those other nations to oppose you.

[mmooss]

The US isn't a nearby nation and doesn't want to expand by seizing countries anywhere, especially in the Mideast.

None of Iran's neighbors - e.g., Iraq and Afghanistan - want to or have any capacity to invade Iran. A destabilized Iran is a nightmare for them.