First folks started to find that Kydex wasn't the devil and started accepting hybrid holster instead of all leather. The was years ago.
A coupla years back, I notice
SayUncle, and then others, go from calibers that began with a .4 to 9mm. The idea was more is better than less ammo in a gun fight. And 2 hits with a 9mm is better than 1 hit with a .45. And you might as well, post 2004, when magazine size limitations were in the rear view mirror. If you aren't restricted to 10 or less, might as well go for quantity and it is easier to get quantity with 9mm than .45. Plus, pistols are pistols. If you want a qauntum increase in round effectiveness, switch to a rifle. 9mm is also easier to control, obviously, so shot placement is better for shot #2.
Anyhoo, 1911s in leather IWB holsters give way to M&P 9mm in kydex IWB holsters.
Now, the SayUncle bellweather has notice a new fashion trend.
Appendix carry. With it's pluses and minuses. It's faster, but there is a risk to the femoral artery. Maybe this will stick, too.
And this doesn't count 'fashion' trends in history. Like the 'Wonder 9' trend of the 80s that went away and then came back. The .45 trend already mentioned. 6 o'clock IWB for a time, I believe, was a 'thing.' (Thank you Eddie Murphy's 'Axel Foley') The .380 pocket auto was huge for a while. The post Miami shootout that got 10mm popular for a time, and then .40, and from that .357 Sig, and all 4 are fading now. CCW doesn't go very far back beyond that, but I am sure there were other trends for various firearm and firearm accoutrement selection decisions before CCW was a thing. Shoulder holster carry, I guess.
There were reasons, of course, for each trend swing, but not really HUGE ones. It's just 'cuz,' kinda, really. It's all in pursuit of making oneself a more effective shottist, but it's also splitting hairs to the point of being similar to the clothes fashion world. I mean if the trend were to go back to 1911s folks wouldn't really be handicapping themselves. Or even back to revolvers. It just seems sort of fickle.
Not a criticism, just an observation.
But I wonder what the next trend will be?