But the part about the undersea cable is simply wrong! Major undersea cables have been disrupted several times and never has a "continent gone dark".

I think this betrays a severe misunderstanding of what the internet is. It is the most resilient computer network by a long shot, far more so than any of these toy meshes. For starters, none of them even manage to make any intercontinental connections except when themselves using the internet as their substrate.

Now of course, if you put all your stuff in a single organization's "cloud", you don't get to benefit from all that resilience. That sort of fragile architecture is rightly criticized but this falls flat as a criticism of the internet itself.