It is what the Iranians have repeatedly demanded.
Of course this is what they are
saying, just like the U.S. is
saying they have the capability of sustaining the war indefinitely. You never, ever want to project any sort of weakness in the midst of a conflict, even if you
have been weakened by your opponent.
Especially if you have been weakened by your opponent!
This is wishful thinking. The Chinese are the beneficiaries of US military resources being squandered on a futile war with Iran. They know the US China hawks are having fits over the depletion of weapon stockpiles. Russia likely also knows that the cycle will just repeat if the US and Israel are let off the hook. Besides, they are making an absolute fortune from increased energy prices. They will happily see it go on a good while longer. It also means less weapons for Ukraine.
Both Russia and China benefit a lot from US bleeding itself out in this: dependency on Russian energy grows and gives them leverage over Ukraine and EU, their stock market grows and for China depleted US means bigger possibility of capturing Taiwan plus US economy would buckle much sooner than Chinese in this oil crunch. Their problems pale in comparison to US's problems. If Iran gains offensive advantage, short of nuke being dropped, there is no reason to stop until it gives US/Israhell a black eye.
While it's true that this war is weakening the U.S. (which would obviously seem to benefit Russia and China as America's rivals), I think the leadership of those countries is very conservative and pragmatic, and would prefer not to risk the chaotic and unpredictable downstream consequences of this war continuing. China is and has been playing the long game masterfully, and Russia under Putin is extremely practical in its approach to statecraft. The fact is, they don't
need this war to weaken the United States; our own woeful policies have been doing a stellar job of that without any foreign interference. But for all of America's faults, it still possesses the most formidable military in the world, and a frightening nuclear arsenal. That's not something you want to play around with if you are Russia and China, especially if you increasingly regard the leadership of the U.S. and their Israeli allies as dangerously delusional and unhinged (which they apparently do).
Russia and China want to stand by as the U.S. slowly bleeds out, they don't want to directly confront them and trigger a conflict that could lead to global nuclear war. Nor do they want to see the U.S. fall into such a desperate position that they do something incredibly stupid like launch nukes at Iran, a possibility that while hopefully remote, grows more likely the longer the conflict drags on. That is why I predict that both Russia and China will use their considerable leverage over Iran to encourage some sort of peace deal. Of course, perhaps I am misreading the situation and you all are correct. We shall see.