The issue isn't that states are responsible for education. Mostly.
Germany's constitution prohibits the federal government from nearly everything relating to education as a defense against a possibly fascist federal government. So much in fact, every time the federal government wants to subsidise anything - even as simple as aiding in school renovations - a constitutional amendment has to be passed.
The reason it works (for the most part) is because of the Kultusministerkonferenz - the conference of ministers of education. While there are still somewhat significant differences between the states, they have standardized vast parts of education amongst themselves. This ranges from mandating the teaching of English as a second language to outright changing German orthography in 1996.
As a result, basically all universities in Germany have similar prestige. Sure, some of the larger one's are better known but you have pretty much free choice where you want to study without hampering your future employment. The exceptions are private universities – everyone will believe (for good reason, may I add) that you basically purchased a degree and are incompetent.
Though now I wonder: Does the US actually have any voluntary body of states that makes standardized decisions for anything? Like education, justice, police, etc. Or do you states insist to do everything their own way because talking is communist or something?
