We know the answer to this one already
Germans did not do anything about Hitler because the wealthy & influential didn't want to pay taxes, refused to fix a financial mess they made, refused to pay war debts for the conquests & looting they demanded
Instead they ginned up hate campaigns & more wars
Billionaires & bigots, the forever alliance made in hell
https://www.counterpunch.org/2021/05/26/the-nazi-past-of-us-geopolitics/
https://www.newyorker.com/magazine/2018/04/30/how-american-racism-influenced-hitler
https://read.macmillan.com/lp/hitlers-aristocrats/
https://www.publishersweekly.com/9781250148957
https://www.nytimes.com/2024/08/14/books/review/richard-j-evans-hitlers-people.html