Most academics really want to improve their writing, because good writing increases your chances of getting your manuscript accepted. Still, I think the academic system doesn´t reward good writing as much as it should.
The best advice I´ve seen recently on how to become a better writer is this quora post by Venkatesh Rao. He pins any quality improvements to rewriting:
The HUGE difference between everyday writing that everybody does and serious writing is the proportion that is re-writing. I’d estimate that for non-writers, rewriting accounts for maybe 10-20% of their writing. For serious writers, it accounts for anywhere between 50-90% depending on how critical the particular piece is.
I´m not sure how much rewriting goes into your average paper, but those numbers ring true for me. This makes things simpler: if you want to improve as a writer, focus on your rewriting skill. This is solid advice. Now I understand why doing revisions of a paper feels so tiresome: it’s not necessarily boredom, it’s the fact that rewriting is more effortful than actual writing.