Repealing Obamacare. Reforming the tax system. Spending big on infrastructure.

One by one, President Trump’s campaign promises seem to be less likely — or at least won’t happen on the timetable he anticipated. So, why are so many chief executives and investors still seemingly bullish about a Trumpian economy?

The answer they consistently provide: regulations. Or the promise to get rid of them.

But it is actually something else, something that seems vastly underappreciated, that is staring us right in the face: The people whom Mr. Trump has appointed to positions of power can wield significant influence over how business is conducted in America. And in many cases, they can do so unilaterally, without the approval of Congress.

The presidency of Donald J. Trump — the wealthiest businessman to occupy the White House in recent memory — has ushered in a new paradigm, one in which business and government are married in a way never seen before. And the people whom Mr. Trump has appointed come from the most senior ranks of business, bringing with them a frame of reference that is almost strictly about profit and economic growth.

It isn’t often said aloud, but the aristocracy that Mr. Trump has put in place may be more important than any rule written on paper.