I am very very familiar with the German system.
There is a difference between “allowing” anyone to go to university if they qualify and having a society that actively works to give kids a solid non university path that is valued by society. In the US we do NOT do a good job of that. Kids, of all abilities, get the message from a young age that success lies only in the college path. We do a terrible job of validating alternative education paths. We also do a terrible job of career counseling. Hence the number of people with advanced degrees doing jobs you barely need a college education to excel at.