Pop-sci / self-help I feel is particularly egregious in this regard. Like you could take the entirety of many self-help books and summarise them into a few bullet points.

Though having said that, if the ultimate goal of writing is to transfer one person’s experience of human thought to another, then the filler often makes sense. They’re trying to take you on the same mental journey that they went on. At least that’s the good-faith interpretation.

I think filler is also akin to the difference in experience between listening to an audiobook at 1x speed vs say 3x speed. The slower pace gives your brain time to work.

But I totally agree, once you know a bunch about a subject the filler becomes unnecessary.