Agreed, but Trump doesn't know that. He will absolutely love showing off a trade deal and rubbing it in the EU's face.No offense, but most Americans care less than zero about a trade deal with the UK. Even less so swing voters in Battleground States. They don't see it as having a significant effect on the US economy much less their local economy and their lives.
The only people who really care are the Cosmopolitans on the West Coast and Northeast. Most Cosmopolitans are on the Left and want to punish the UK for leaving what could potentially be the kernel for a secular global government. So no other polity ever considers voting to leave again.
Atlanticist would very much like to a see a US-UK trade deal. There are too few us to make a difference in any State.