DD, for me it's not a trend. I started riding tubulars on the streets of Chicago when I was 18 and bought a bike with tubulars. It took a while to learn how and where I could get enough pressure to harden the tire (21 mm cottons, I was afraid of destroying the skinny little rims in the first month of riding). I also noticed harshness and did not have the spare $$ start fine tuning my tire selection. I didn't even own a capable pump, beyond the Silca Impero that came with the bike. I tried just bleeding down the tires a tiny bit, and whatever I accomplished helped the ride a lot and did not make it feel slower. I also did not start destroying rims. After I had a Silca Pista, I could see the pressure, and the good spot was between 90 and 100. That's just the way it worked.

I never timed myself, so I don't know if harder was faster (typical roadie wisdom, even in the 1970s), or if a little softer was faster (Bicycle Quarterly wisdom). I just know I liked the 95 psi area a lot better than 110 and up.