I'm in my home office, sorting old papers. And of course reading some of them. Apparently, in graduate school I was able to write clearly and analytically, at length, about complicated things like privacy regulations in the EU. There is little poetry, but there are thoughts, conveyed in English, by words on paper. There is clarity. There is precision. There are ideas that carefully build upon each other, in crisp sentences, stacked in well-ordered paragraphs, to a logical conclusion. (There are also too many commas and horrible typos, but that's always been true of my writing.)
I've had a Theory for a while (which for this post I've given a field promotion to Law) that explains why graduate school was the peak of my writing ability. It is not because of age, or because I write less now. It is because of PowerPoint.
Reffell's law: For every year you write seriously, starting around Kindergarten, you get incrementally better at writing. And for every year you write serious amounts of PowerPoint (or Keynote) in a corporate environment, you lose one of those increments.
That's put me back, effectively, to my senior year in high school. (The startup years don't count for this, there's a low PPT count.) That's not so bad! I was a pretty good writer in high school. Better than a lot of adults. But it will go seriously downhill from here. Another two years and I'll be at 10th grade; two more and we'll be in middle school. Quickly we'll be in "Dick and Jane go up hill" territory.
I think, by the way, this is specific to intra-corporate use. Something about the highly concentrated jargon, shared assumptions, and positioning of cliches (verbal and visual) as a means of bludgeoning the decision-making apparatus into submission. Probably the decks you build for public presentations are safe. Probably.