The PPL issue is a fascinating one to me too.
I've always known that men's dress slacks are supposed to break in the front (near the ankle) - which means they are intended to be long. I think I learned this somewhere along the line as a kid, watching my dad get his business suits tailored.
As for women's slacks and jeans, reaching far back into my memory:
- in grade school (70's) we wore light-wash bell bottom jeans and I seem to recall they were supposed to drag along the ground, driving my mother batty because they'd get all ratty on the ends. Until we grew a few inches, then they'd become floods and we'd want new pants but my mother would hold off, driving us girls crazy! If you wore such "floods" you'd get mercilessly teased on the playground!!!
- in junior high (late 70s/early 80s) bell bottoms went out of fashion overnight. Everyone switched to dark wash straight legs or cordoroys in a myriad of colors (from the Gap). You wore them tucked into your cowboy boots, so having them on the short side was more convenient.
- in high school (early 80s) bootcuts and the first designer denim (remember Jordache?) came into fashion, just as knee-high boots went *out* of fashion. But there was also the whole preppy trend, wearing basic Levi's or Gap jeans, but requiring you to cuff your jeans a few inches. Either way, you wanted to show off your argyle socks and your docksiders (with the laces artfully tied). So short pants were definetly preferable. (Also you wore a pastel button down shirt with a sweater wrapped around your neck just so.)
- in college (mid 80s) skinny jeans (often acid washed) came into fashion - preferably ankle length with zippers at the ankle! You wouldn't want them too long, or the zipper would bunch up funny. I remember hating this fashion trend because it was nearly impossible for me to find zippered pants just the right length.
- in my early career days (late 80s, early 90s) it was all about the regulation Nancy Reagen Red Power Suit with Ginormous shoulder pads (bigger the better), knee-length skirt, nude pantyhose, and high heels. Don't remember wearing jeans during this phase. On weekends, I'd wear a dress to go out or (shudder) neon colored sweatsuit (one with Shoulder pads!!!!!) to run errands.
I must've had jeans or pants to wear on weekends.... just can't recall ... except one pair of high-waisted black dress pants... but I forget how long they were.... oh yes, now I do remember high-waisted, pleated slacks - that were skinny at the ankles. You wanted those ankle length. Worn with heels. And... omg... yes, I seem to recall "mom jeans" before I was a mom: light wash, high-waisted, skinny at the ankles.
- Stay-at-home mom years from 1992 to 1997: I never wore jeans. If I was out and about, I'd wear black pants that were cut like jeans - more stretchy. Or I'd wear sweats, the kind you could buy at Wal-Mart. Or I'd wear stirrup pants!!!!! Lots and lots of stirrup pants with oversized sweaters. This was a dark, dark era... but I do have to say, those stirrup pants were quite comfy!
- Restarting career era from 1997 to say 2001 (when I was laid off in the dot.com bust): I learned to wear dress slacks as my nod to "business casual." Length? I'd have them break at the ankle, if at all possible. This is also the period of time I gravitated towards khakis for weekend wear. I had many khakis from the Gap that were their "Ankle" length... which on me is long if I wear flat shoes, too short if I wear heels. Which I would anyway.
- Starting-to-get-a-clue era (2002 to 2007): still wore khakis. Tried a zillion jeans, none of them very flattering. Still wore dress slacks to work. Paid no attention at all to PPL. I do recall having a pair of perfect black dress slacks (still have them) that annoyed me endlessly because they were - guess what - PPL!!! I kept meaning to get them hemmed, because, especially when wearing strappy sandals, the back of the pants would get stuck in the shoes. All the rest of my dress slacks were most definetly NOT PPL. But I thought they were. Seeing my history.... who could blame me?
- Style makeover era (2007 to present): slow dawning that pants are *supposed* to be long! I think this did dawn on me earlier than finding YLF; it was YLF that spelled it out in writing. Before I found YLF, I had noticed that fashionable women were wearing their flared and wide leg jeans long enough to touch the ground, so no shoe showed at all. I still have to admit... part of me likes this look and considers it uber-trendy .... but part of me still thinks "what happened to her feet?"
But yes, during my last closet rotation, I went through all my pants and tossed out any pants that were ankle length. GONE. I did keep a few slacks that are not touching the ground with heels - they are maybe 1 inch above the ground, long enough for ankle to not show, but short enough they don't get caught in the back of your heel, and don't get all dirty dragging on the ground either.
So there you go.... personally, I think it's all a fashion thing, no more no less. I would bet money that sometime in the next 10 years, we will all be scrambling to hem our pants shorter!