The Manhattan project was a result of a pretty critical situation (the beginning of the nuclear race), and was started by a Nobel laureate, a radical reformer of physics, with a group of other physics luminaries. Not billionaires, but much more rare birds.

The interstate highway project was arguably taken during a very deep and long-lasting crisis by the off-the-charts administration of FDR, who served three consecutive terms, despite whatever traditions, and deeply reworked many American state institutions; talk about overconfidence.

I'd say that the peak power of a POTUS is larger than that of a billionaire; the latter may have a longer planning horizon though, and put in effort and resources for a couple of decades.