That's all well and good until the German Empire decides that it could use some New World colonies and decides that a rich and isolated America would be the perfect target.
There is more yellow-cake uranium in Iraq than there is, ITTL or IOTL, a German naval capability or desire to directly attack the United States beyond u-boats in wartime; they also never got any farther than a merchant community in Haiti when exploring options in the Caribbean, where there is also Britain to worry about.
Posturing was necessary in Europe; less so in the pre-nuclear age for a two-ocean power with yuge industry and, worst comes to worst, big mountains keeping the heartland safe past the coasts.
To quote Lincoln "All the armies of Europe and Asia...could not by force take a drink from the Ohio River or make a track on the Blue Ridge in the trial of a thousand years."
Besides, if they want Free Real Estate (TM) they have more than enough of it dragging them eastward...