Most documents do not want or benefit from interactive elements. The desire is a static representation which renders and prints the same everywhere - and PDF is that format. Everything reads it. Nearly everything writes it. It supports all of the essential functions.

PDF reigns as kings because of the ability to represent graphics as well as text formats easily and ensure that compatibility doesn't break on any device that can render it. It is not the same with HTML, and other media file formats, such as Office docs didn't work on MacOS for a long time and on Linux until recently,this dilemma of having a software but not being able to share the file format, across ecosystems and devices limits the ability of adoption of many other standard documents.

I get all the interaction I want and much more that I don't in my web browser. Non-interactive documents are a Good Thing. Also I like that I can send it to anyone and be sure they'll be able to read it, that it will look the same if its printed etc. And I print myself for some long documents.

There is such a widespread standard and it known as "html". More popular than PDF ever was.

EPUB is also html, but zipped and sometimes crypted.

Unlike "Word" documents, PDFs are a self contained file that almost always renders the same, screen and paper. Of course there are exceptional files, but they're rare and regarded as bugs, rather than shrugs as with "Word" docs.

Specifically regarding videos: Why would I waste an hour of my time watching somebody rambling on, when the edited transcript can be skim/read in 5-10 minutes? It might save the author/presenter time to just record a video. But in turn it wastes thousands of hours of other people's time.

Yeah, I get it, some people can't be bothered reading anything longer than a tweet. Those same folks watch TikTok instead of hour+ long video presentations.

Businesses want businesslike documents, and mere PDF already has enough security issues. What you're describing sounds far too much like Adobe Flash.