Breaking ties with US was unnecessary because Iran and US both recognize each other and now Switzerland is acting as a intermediary between Iran and US. The embassy siege was an emotional act and also damaging, not to forget in what followed (Iran-Iraq war) being deprived of spare parts and US supporting Saddam. Guess what, all 3 organizers of the embassy siege are now reformists!
We could be their enemies/rivals without breaking official ties. We could be an independent country like today without breaking official ties with US. If we look at US-China relations, while both are rivals, they do still have diplomatic relation.
But when it comes to the thieving zionist state, it's an irrelevant small US subsized colony with 7 million zionist jews in it. It's the 51th state of USA and serves as a disruptive sattelite of US goals in middle east. It's a garrison of US to control the middle east and a jewish project/experiment.
If we want to deal with US, we'll go directly to them, not their illegitimate bastard child Israel. I dont even care or think about Iran ever recognizing Israel just as I dont carr about increasing or decreasing ties between Iran and Nauru.