Young academics try to signal that they know what they’re doing so they end up cargo-culting dense technical writing that they can’t yield well and just end up with bad writing.
It takes a lot of confidence to write academic material in a natural conversational tone because they’ve internalized a rule that says “if it’s easy to understand, I won’t come off as smart enough to belong”.
Confidence and support.
I wrote my 45 pages PhD thesis (physics) in a more conversational tone, using "I" and skipping the introduction (half a page to say that if you need an introduction it is better to read this and that, instead of poorly copied pasted text here).
I got a 5:2 acceptance from the jury (which is extremely rare, normally this is 7:0), with the two saying that the content is very good, but I am desacralizing science... I told them that I am proud of these two rejections there and my wonderful thesis director (truly a fantastic person) jumped in to avoid some brawl :)