Iran has been preparing for this war for almost 50 years, and they have more leverage than Vietnamese or Talebans had.
The US is not doing amazing in this war but no need to give the Iranians too much credit. The Iranians are expanding a lot of resources of their own as much as this war drags on.
It is still very early to say how a country will fare considering that it ran out of water and was on a verge of economic breakdown and revolt before fighting a prolonged war with economic blockade of its main export.
In any case, Iran is not in a prime position either, it has many economic assets that can be completely destroyed as it has no air defense and then leave them in a much worse situation, while the only real damage they can do to the US is by attacking their own neighbors