Germany is (until recently) also ethnically homogeneous, unlike the USA.
Its a lot easier to offer those services when everyone has roughly the same income, the same education, the same IQ, the same genetics, the same family experience.
If by until recently you mean the 1960s, maybe? Why do people always assume that there wasn't any immigration to Germany before 2015? https://en.wikipedia.org/wiki/Gastarbeiter
It's so boring that in every discussion where some other country does something better than the US, people find a million reasons why this could never work there.
Its a lot easier to offer those services when everyone has roughly the same income, the same education, the same IQ, the same genetics, the same family experience.