I hope the copyright gets invalidated, but unfortunately it won't set any interesting precidents. They aren't arguing that it should be invalidated because it is fucking old, which honestly, is why it really should be invalidated. They're arguing other stuff that will actually work in court. The supreme court (sadly) has already decided that "it is fucking old" is not a reason to invalidate a copyright. So, we're left waiting for the legislature to reign in copyright law, which of course they'll never do.
Copyrights should last ten, maybe twenty years, tops. None of this death of the author + 70 years bullshit.