It's more than just the 7 countries. People know when they aren't really wanted. Why travel to a country where some dumbass redneck in a Trump hat might take exception to your accent and put a cap in your ass? F that. People will just fly to Thailand or Australia.
Actually something similar has happened to Russia. I had a chance to take a tour of Moscow, Novgorod, and St. Petersburg back in the summer of 2008. The tourism there was incredible: from the Kremlin and Red Square and top tier Moscow shopping and restaurants, to the historical palaces of the czars, museums, and WWII memorials in St. Petersburg, the place was packed and swarming with tourists from all over the world. I remember the palace of Peter The Great was so packed that it was hard to walk around, and the guide for each tour group had to have the flag of their country held up high so the people would know where their tour guide was. As we were walking around, you could see just about every flag on the planet, and every corner of the palace a different language was being spoken: Japan, China, Brazil and other south American countries, the US and Canada, Italy, Germany, France, UK, Australians, Iranians, all sorts of Arabic countries, Turkey, etc...
I remember on our first afternoon in Russia we came form the airport via shuttle and checked in to this fancy hotel in downtown Moscow. I was totally jet-lagged and exhausted, and so I just plopped down on the bed and started flipping through the TV channels. I don't know much Russian, so I stopped at the English speaking channel RT. It was a very interesting interview with Medvedev. They were talking to him about the possibility of Russia joining the European Union, and Medvedev was very seriously talking about the pros and cons of such a move. I couldn't believe it! Russia joining the EU! And then even more surprisingly, they asked him about Russia joining NATO. My jaw was on the floor. But not Medvedev. He just smiled and said that he believed that might still be a ways off, but that even that would be a possibility that Russia would be willing to entertain in the future. I couldn't believe it.
But my, what a different world we live in now. What a difference a few years makes. I think if such things had come to pass, with Russia as part of the EU and even part of NATO, rather than such a bitter rival, it would have been a win-win for all parties involved, including the US. So what happened? Unbridled nationalism, paranoia, fear, aggressiveness and lack of consideration for the international community, thinking that their glory days were behind them and the way to get it back was through military might, intimidation, bullying, fear, bossiness,... ie, "make Russia Great Again".
The tourism in Russia has taken a bit hit since then. Its reputation as a civilized country in the community of nations in the world is gone. They are just a pariah state now, ostracized by the rest of the world, except perhaps the Syrians and Iranians.
My concern is that this sort of shortsighted aggressiveness, rudeness, selfishness, etc... that led to Russia becoming the pariah state it is now, are the same characteristics which the new administration is putting on the US. The world has traditionally looked to the US as a place which championed human rights, a place they could look to for justice and fairness in a world where such things are in such short supply.... but no more.
So forget the tourism. I think the US has taken an irredeemable hit to its international reputation with the election of someone with such a crass and boorish personality as Trump to be the new face of the country.
, they are the Northern Europeans of European tourism 
