Yes, a lot of the loss of German culture in America, including the food culture, comes from the assimilation of Germans into "American" society. It's not because the German food isn't good; it's some of the best. But when we speak of German assimilation in America, let's not forget that a good deal of that "assimiliation" is more like "expungement." A lot of it was a conscious political choice, likely associated with the inability of many Americans to separate in their minds their German-American neighbors from the instigators of two certain intercontinental disputes that pre-occupied Europe and the Americas during the early and mid-parts of the twentieth century. German-American culture is clearly not dead yet, but it was mortally wounded and it won't ever be the same.
Here are two little examples I know of; perhaps you know some more. In my hometown of Indianapolis, as German a town as there ever was in this country in the late 19th century and early 20th, German culture went from the pride of housing dozens of German-American social and political associations and as many as 26 German-language newspapers, to the shame of changing the name of a key cultural institution from "Das Deutsche Haus" to "The Athenaeum" in 1914 -- and it wasn't because it was bought by the Greeks. Here's another example of how German-American culture was erased from memory (almost) in Indianapolis as part of the war effort. Currently in that city is a curiously named street called "Bosart." For a while, it was "Bozart." Before that (and until about .. oh, 1914) it was "Mozart." Ponder that a while.
Prior to the first World War, being part of one of the "right" German-American families in Indianapolis was like being a member of the Rotary Club, a Mason and on the Board of Halliburton, all rolled into one. I have to guess it was about the same in Chicago, Cincinnati, St. Louis, etc. That may not have changed overnight (indeed, I suppose the financial and social status of the German-Americans didn't change a whit, if they were willing to drop the old-fashioned accents and start calling themselves "Bill" instead of Wilhelm.) But certainly, for about 40 or 50 years there, one didn't casually wear a "Kiss Me, I'm German" t-shirt.
The unfairness and perversity of this should be obvious, as we're talking about German-
American culture being erased, not Kaiser Wilhelm's color guard being asked to stop marching around the Circle. These were Americans of German heritage who were probably victims not only of their fellow citizens' misguided xenophobia, but also of that peculiar form of German shame others have noted here before. I say this because the German-American community in the Midwest in the 20th century (at least in the urban centers) was in a position of economic and political superiority where presumably they didn't have to stand for being oppressed or having their cultural identity expunged, but probably chose it (or allowed it to be imposed) themselves.
So now I've identified the problem, what is the solution? To the extent German-American culture has managed to hang in there at all in this country, it's probably due to that other characteristic German trait of stubborness. And that of course is a key sign of the real problem. Stubborness isn't cool, and Germans aren't cool enough -- or at least not
perceived as cool enough -- in a thousand other ways. In the popular mind, Germans are still seen (falsely) as monocle-wearing war monkeys who find moral worth in overstarched collars, or else as foot-slapping, lederhosen-wearing buffoons. That's an obvious slander that needs correcting, but it's all an image problem of the sort that modern America was created to fix. What German-Americans (and those who love them) need to understand is that they need to forget such old-fashioned concepts as "pride" and "intellectual rigor" and "stuffy old country values."
Coolness is the only value that matters today -- and there is nothing more cool than being oppressed. That is, being oppressed is not, in itself, cool, if you are the one actually being oppressed; but your coolness factor among key demographics like college students will rise dramatically if your civil rights are (or can be convincingly portrayed as being) abused. And once you're in with the college demo, it's smoooooth sailing, Heinrich!
Admittedly, this would be an easier case to make 90 years ago (when the German-Americans were more German-seeming than today), but I say let's give it a try. If the German-Americans were portrayed in textbooks, on coffee mugs, in Mother Jones, etc. as an oppressed minority (and anyone who can actually speak German is definitely a minority), it might actually be cool to be German! College students would continue wearing Birkenstocks (which are, I believe, "beyond cool and evil"), but would replace their Ramen noodles with boiled wurst, cooked in the same electric coffee pots in their dorm rooms. Beer also would remain popular among college students, but it would be drunk with greater gemutlichkeit.
But oh, who am I kidding. That won't be happening in our lifetimes. The German-Americans 90 years ago blew it for all of us when they went in the cultural closet, never to emerge ...