I read the article and my first thought was it was entirely missing the complexity of XML. It started out relatively simple and easy to understand and most people/programs wrote simple XML that looked a lot like HTML still does.

But it didn't take long before XML might well be a binary format for all it matters to us humans looking at it, parsing it, dealing with it.

JSON came along and it's simplicity was baked in. Anyone can argue it's not a great format but it forcefully maintains the simplicity that XML lost quite quickly.