If so, it seems he missed the mark (significantly) on web development.
He said "if in a few decades we get a document format on some sort of web of computers, I am sure we will be creating those documents by direct manipulation - there won't be any markup languages or stylesheets, that will make no sense."
So that is either very sarcastic and cheeky, or straight up wrong.
What am I missing?
I was wondering how comes the audience (and video) seems so "current", but the content looks so dated.
I think he's wrong as well. Often non-technical managers assume that since something is simple to describe, it will be simple to implement. This is the tech talk equivalent of that attitude.
Also, there are CMSs and WYSIWYG webpage creators that operate at various levels of success. Markup languages and stylesheets coexist partly because they meet different use cases. For example, I've never heard of a spec for a WYSIWYG "language", so you're guaranteed to have to deal with vendor lock-in and a lack of portability unless you can then generate some text documents in a standardized language.
I also think rational decision making requires some predictions and successful trials before confirming any theses.