Trump's ultimatum in the past 48 hours is, to put it bluntly, more for the voters than for Iran. If oil prices really hit $100, it would basically be political suicide for the U.S. president, and he cannot be unaware of this.
But the problem is that Iran's mentality has changed. After being sanctioned, negotiated with, and having agreements torn up repeatedly over the past few years, they have accepted one thing: talking to the U.S. holds no long-term credibility. So this time, getting them to sit down for serious discussions is much more difficult than before. They are more inclined to first 'show some color' before discussing anything else.
However, many people think of this matter too linearly, saying that Iran wants to drive up oil prices to crush the U.S. stock market; this logic is somewhat idealistic. Today's America is not the same country that relied solely on oil imports; rising oil prices will indeed pressure consumption, but it will also provide a lifeline to America's own energy industry. You might say there will be a shock, but it won't completely collapse the U.S. stock market.
What we need to observe is not whether there will be a conflict, but to what extent it will escalate.
A person like Trump does not need to engage in a real major battle; he only needs the market and voters to feel—he is tough, he dares to take action, but the situation is still under control.
So a more realistic script is likely to be the familiar scenario:
Small-scale actions, proxy friction, localized escalation, and then continuing to make tough statements, keeping the rhythm in a 'tense but not explosive' range.
Iran is the same; it is unlikely to go all in directly. If they were to truly block shipping lanes or launch large-scale attacks on energy facilities, it would drag them down with it. It is more likely they will prolong the cycle, grinding slowly, keeping the situation hanging.
To put it bluntly, this is not a game of who can crush whom, but a competition of who can better control the rhythm.
So your final question—would Trump dare to risk the collapse of the U.S. stock market to blow up a power plant?
A more realistic answer is: he will make moves that 'look daring,' but he won't truly bring the market down with him.