As I understand it, in Europe they give phd students canned projects to work on, which are designed to only take a couple years. It's just the whole plan of how long they want it to take. In the US doing a project of that size may be enough to get by at some schools, but it generally isn't supposed to be.
It's absurd to try to say how it is in Europe. You can't even say how it is overall in Germany. There are various different arrangements with companies, research centers like Max Planck, universities, some are full (state) employee positions, some are half, some give stipends, some take 3 years, some 4 or 5, some make you teach courses, some don't.
Depends on country, field, particular university or company, even the department.
So you can't generalize over a whole continent.
I am not sure what you are referring to, but a PhD in Europe takes 3/4 years. They are generally organised such that you are tied to a single supervisor/research group, which might be where the confusion comes from? They are by no means canned projects, at least as far I know.