You could always remove the walls when the child grows into a teenager. I don't think you can seriously equate a real-life analogy with programming languages without being ridiculous.
I personally believe C# and Java are easier to get up and going and showing the results of CS subjects. I personally believe the beginner to intermediate syntax is much simpler in C# than Java than C++. You can write libraries using libraries, so I don't see your point. Normally we want students writing (hopefully useful) applications, and sometimes libraries, that teach the student something that goes beyond language choice. That just so happens to be easier for more subjects, and more manageable, when a language abstracts certain details from the user (pointers, memory management, templates, etc). There's too many little things to cover using C++ for year 1-2 university courses, at least unless the university has a high admission requirement, where it is to be expected (caltech, mit, berkeley, stanford, etc). It seems like university language choices the last 5+ years would agree. However I do think C++0x will be an improvement, and they could probably get by using C++ with Boost, but it's still a flawed teaching tool in comparison to a run-time language.
We might have to agree to disagree.