On Wednesday night in Miami, billionaires and royals waited in line to get a seat for President Trump’s speech at the Saudi Arabia-backed Future Investment Initiative (FII) summit. Everyone from Trump’s former Treasury Secretary Steve Mnuchin to former Google CEO Eric Schmidt to WeWork founder Adam Neumann queued to get a seat in the conference hall, or even in the overflow area. Moguls texted FII organizers and PR reps for seats directly in the President’s sightline or near some of his most important allies — namely Elon Musk. Neumann, sources said, didn’t have much luck getting inside either room. “You...