You don't have to speculate like this. We can just look at how North Korea is treated, now that they do have nuclear capability. From the Iranian (or Ukrainian) perspective, the conclusion can only be "better than us".
In your hypothetical, we're sending B2s to drop bombs on their production sites. In the reality, we would not do that, for the same reasons that we are not sending B2s to drop bombs on North Korea's production sites.
Maybe. It certainly would not surprise me if you're right--that's why it's the conventional wisdom.
But these kind of events--Israel defanging Hezbollah, US destroying nuclear sites--should change our priors. And it might change priors in Iran too. Until we actually sent B-2s in, Iran didn't know whether we ever would. They might have held out hope that we were bluffing--that we would never risk a $2 billion plane (not to mention a crew) on bombing a site that only sets back the program a couple of years.
Now that the US has done it, what's to stop us from doing it again later? Why bother spending so much effort on a program that gets blown up every few years? Maybe they'll just try to hide it better, but can they really rely on not having intelligence leaks, given the massive intelligence failures of the past few months?
And North Korea is not a great example. Even if it's true that their nuclear program has deterred us, they bought it at an enormous cost: North Korea is completely isolated. Iran would like to get rid of the current sanctions and start integrating into the rest of the world. Even if the regime doesn't care about its people, it still wants aircraft parts and oil revenue. The US and Israel would be fine if Iran continued to slowly rebuild its nuclear program, as long as it remained under sanctions. They can just wait five years and bomb again. But is that really a victory for Iran?
My point is that these events might cause Iran to re-evaluate the cost/benefits of their current strategy. They might decide that rushing to build a nuclear bomb is not worth the very large costs.
First of all, I disagree with your characterization of what the conventional wisdom is. I don't think most people are thinking about this at all. Most people will come down on rah rah America or boo war is bad, not "it's bad that specifically only countries that don't have nuclear weapons get attacked, because of the bad incentives".
But if this were the conventional wisdom, I'd say that it's clearly right, and you're doing 5d chess to avoid looking it in the face.
> First of all, I disagree with your characterization of what the conventional wisdom is.
Okay, you could be right about that. I don't know.
> But if this were the conventional wisdom, I'd say that it's clearly right
That's really the crux of the disagreement: I don't see it as being clearly right. Maybe I'm overthinking it. Maybe it's biased reasoning on my part (wouldn't be the first time). But I don't think it is obvious how the Iranian regime is going to react. I don't think any one person inside Iran knows how the regime is going to react yet (maybe not even the Khamenei).
It sounds like you think it's obvious how things will play out. That's cool, but that's where we disagree.
In your hypothetical, we're sending B2s to drop bombs on their production sites. In the reality, we would not do that, for the same reasons that we are not sending B2s to drop bombs on North Korea's production sites.