The reason we are still with bases in the EU, is for strategic positioning....if we had a problem with China, we have military that can approach them from the east and west....not just from our west coast, the same with Russia, along with protecting the EU from the then Soviet Block Nations abutting them...
Also, we have most of our eaves dropping done from there on Russia and I would suppose, the middle east, now that we lost our bases in Saudi Arabia, under Bush, and also after we lost our Air Force Base in Tripoli, Lybia.
I am not saying we still need all of the bases there...maybe we could consolidate some more there to save money, but one thing I am not, is foolish enough to believe we could just simply shut them all down...
My father was Stationed at one of these NATO bases in Northern Italy, and he worked in a Communications Squadron, and even though my sister and mother and I were allowed to travel on our passports to Czechoslovakia and Yugoslavia...two soviet block countries, my Father, due to his top secret clearance of the highest level, was restricted by the Air Force from traveling there....so times were still very tense with the USA and the Soviet Block countries controlled by Russians....
and even in the USA to this very day, most hacks that occur on our Government sites and email, comes from Russia and China, most spies caught were working for Russia....things are still NOT as lovey dovey as you all, and the Trumpster imply.