I hope withdrawing the Army isn't a serious proposal. Because it is too useful to lose:
The Pentagon is analyzing the cost and impact of a large-scale withdrawal or transfer of American troops stationed in Germany, amid growing tensions between President Trump and German Chancellor Angela Merkel, according to people familiar with the work.
I have no doubt that basing troops in Germany saves money.
Further, adding brigades during a crisis is far more provocative than simply already having them there.
As the article notes, America gains advantages with troops in Europe:
Since the end of World War II, the U.S. troop presence in Germany has been viewed as a bulwark against a potential Russian invasion of Europe and a staging ground for U.S. operations in Africa and the Middle East.
I argued on both these grounds fifteen years ago (starting on pg. 15) that we should keep a corps there with five brigades forward deployed.