I think you're right about US education skimping on WWI, but I will say that in my fairly terrible white working class high school, when we inevitably ran out of time in the US history survey class, my teacher made an unusual call. He reasoned that we would learn about WWII through pop culture and other things, but that WWI was important and under-studied, so we learned US history through Reconstruction, then leapt to WWI, then leapt to the Vietnam War.

I have some critiques of this--among other things, I think history does not equal "war" and we should have gotten the Gilded Age and the mass immigration of the early 20th c that was responsible for all our grandparents being in the country--but I do see his logic.