Pre 1973 LPs are considerably thicker than post 1973 LPs. The LPs of the late 70's were of real bad quality.
When I got my first CD-player in the 1980's, I had the chance to compare some original LPs, to new CD versions. The CDs revealed details I could not hear on the LPs. And mind you, that was the cheapest CD player available, and a good, mid prized turntable (Rega Planar 3/Elys cartridge). And it was pre 1973 LP's.
In the old days conventional wisdom was that the vinyl of an LP would deteriorate with time, and after about 30 years the chemical changes in the material would have affected the grooves so much that the sound would suffer audibly.
I've got records that almost 40 years old, and it's true the sound is bad. Whether this is caused by deterioration, wear, or bad quality in the fort place, I can't tell...
Anyway, what today's vinyl fans seems to forget, is that vinyl records are worn, even with high end players.
Sony / Apple / Rega / AVI