The more important question is, under current circumstances, how long can Iran actually fight? If Trump does decide to go against his instincts and opts for the long-haul fight, Israel will not back down either. And in these weeks, certain replenishments and deployments would also have been made to cater to restarting of hostilities.
Consider the scenario that talks fail and hostilities restart, and Trump does act on his threats and targets civilian Iranian infrastructure such as Oil producing facilities, Energy Infrastructure / Power Plants, Dams / Water Reservoirs, Bridges and other critical infrastructure......where does Iran stand? We can imagine complete blackouts in Iran with shortage of power, gas, water, air pollution, shortage of food, medicine etc.
The worst Iran can do is inflict pain on GCC countries, which will eventually compel them to engage Iran with their own offensive weapons. That literally means tens of thousands of attacks on Iran daily with GCC Air Force and Drone resources. Moreover, the GCC can also acquire tens of thousands of drones very very quickly from various global suppliers. Iran cannot do that.
Iran will eventually run out of weapons and stamina, but at that time Iran will not be forgiven and will be pounded back to stone age. We can even consider considerable damage to GCC countries in all this, which means Isreal emerges a lot stronger, with literally no rival in Arabian Peninsula. US achieves all this without using nuclear weapons (except maybe tactical battlefield Nukes to annihilate the Iranian frontlines, if US decides to go for boots on the ground).
I continue to think that Iran is not as strong militarily as it postures to be, infact Iran is actually able to bring the US to the negotiations table simply because Trump needs to stop the war else he may lose the majority he has in Senate and eventually the Presidential Elections loss for his party in the next General Elections. Militarily, Iran has nothing to compel the US to negotiations. And if Trump orders the US Navy to open and protect the strait of Hormuz, I doubt Iran can continue to threaten it for too long.
Having written the above, Iran cannot negotiate on its Missile program but will have to lower the enrichment of its fissile material to IAEA acceptable levels. The US will have to lift all sanctions and will have to release Iranian assets seized all over the world. With freedom to sell its gas, oil and other resources, Iran will be able to rebuild quickly including militarily. Iran can even build a very strong Air Force in the next 5-10 years. But for all this, Iran will have to accept limitations on Nuclear ambitions.