Many professionals (not only scientists) are really bad at crafting sentences and texts, even without jargon.

I get jargon, but even if you replace all of the jargon in a typical paper with simple words, the writing style is often horrible. It's often weirdly repetitive, has fluff-pieces and empty phrases, and just doesn't get to the point. (I'll ignore the inherent worthlessness of many articles here, since this is a symptom of funding policy)

I don't expect a scientific article to be understandable for someone outside the field, but do yourself the disfavour and ask a random scientist, what it is they're actually doing and to explain it in simple terms. Most can't. And that says to me, that these people never learned (or were taught) how to actually boil a concept down to its essence. And that I think is pretty bad.

As an example, two scientists from different fields could work on almost the same problem from different angles, but they would never know that if they talked to each other, because they are unable to express their work in a way the other person can understand.