[apl]

  > Channeling people into vocations at 18 [US system]
  > or 10-13 [German system]

Don't exaggerate. Yes, it's true that there's some segregation going on at that point (Gymnasium versus Hauptschule versus Realschule), but the boundaries are permeable.

Even if one assumes that students stick to their "path," that doesn't mean that they don't have a choice over their vocations later on. You're free to do whatever you want. Most students start their first degree when they're 21/22. 30-35% (IIRC) change "major."

I wouldn't say that HE flexibility is a specifically American strength.