Angelina Jolie is probably right in her assessment that the modern education system is not geared to catering for her children's needs. Her jetset lifestyle means she has the choice of enrolling her children at a private boarding school (state boarding provision is relatively limited throughout the world) or having them taught by tutors and teachers while the family is on the road. Boarding education is not suitable for every child, and not every parent wants to farm out their offspring to somebody else's care simply because they have a job which involves travelling.
The international lycée system, which provides nannies and tutors wherever they happen to be, is probably her best bet. There is, of course, hands-on, home education, although it would be hard to imagine this happening over the Jolie-Pitt kitchen table.
Home schooling can work for some, but it takes a dedicated parent with a working knowledge of a range of subjects.
For the outgoing child, home schooling may not provide enough contact with other children of their own age to form friendships with.
Having said that, Jolie and Pitt seem to have a sufficiently large brood to counter that difficulty.