The celebration of German heritage took a big hit with WWI and WWII. But it has recovered quite nicely since. I think part of it is that many german immigrants got here relatively early in the nations history. Because of that many customs and practices, foods, language etc. have become so ingrained in American culture that most don't realize they're German. Fried chicken, for example. In modern culture it's considered a southern dish. But what is probably the fried chicken capital of the world is Frankenmuth, Michigan, with 2 restaurants (owned by the Zehnder family) serving the best fried chicken in the north.
CC
Actually Germans are the biggest immigration group ever, from colonial all the way through at least c. 1900. I don’t know why no one notices such a huge population, maybe partly what you mention, but Germans never seemed to make much over themselves. Never made waves, per se.
My family is very German both sides. Mother again recounted today how anti-German people were from WWI, but not so much WWII. Her family had a local meat-packing plant and they experienced much more boycotting, etc in WWI than the latter. Mom lived through the latter albeit very young, and never felt prejudice.