No he most likely knows. He's gaslighting the people who are watching. What's the simpler answer here? Well educated billionaire doesn't know how tariffs work, or he's lying through his teeth to protect his interests?
He literally can't imagine anything more complex to manufacture than the Trump tat he imports already. Hats, flags and T-shirts, etc. Things that could be swapped to US manufacturer in a matter of months.
The complete supply chain for an iPhone would melt his brain.