86 year old fanatical Islamists don't necessarily operate on the same principles of game theory as the rest of us. Mutual self-destruction is not something they fear to the same degree.
And yet, for twenty goddamn years now, they’ve been negotiating with us and have _not_ built a nuclear weapon, despite repeated threats and provocations by the US. Iran is not an irrational actor. They are a state under siege by a superpower and its violent regional partners, and have acted in the fashion one would expect from a state in that position.
I mean, you're also forgetting the fact that Israel sends assassins after their top nuclear scientists every year or two, and cyberattacks every few years, and "mysterious accidents".
It's a bit like saying "but Y2K never happened, they must have been exaggerating" or "but nobody talks about the Ozone hole or acid rain anymore so it must have never been a real problem".
