The girls looked even worse in the 70's. Too much bush, but the movies did have more plot in the 70's and 80's. Most of these girls lasted only a few years, although ones like Amber Lynn are still around doing the odd scene.
The guys last forever in these movies. Ron Jeremy survived the 80's and 90's. I even think he was in the biz in the late 70's. As the chicks have gotten better and more hot, he's gotten fatter, hairier and uglier but he still gets to bang all these new, hot upgraded women.
Ciao,
VT