The first OPEC oil crisis started in October, 1973, four years *after* RCA introduced Dynaflex records (about 70g IIRC) in 1969. So Dynaflex was *not* a response to rising oil prices. It probably was, in part, for saving money. I've found that Dynaflex records sound like any standard 140g record if you use a record grip or weight with it.
In 1979, OPEC introduced yet another price-gouging, but by then the US had developed new trade relations with oil-producing countries in South America, and the US made it through the '80s with readily available, reasonably-priced oil.
So a well produced LP today was probably better than many 30 years ago... not so much if you go back 40 years.
If you do the math, you'll realize that 30 years ago was the 1980s; 40 years ago was the 1970s, the years of the gasoline shortages, high petroleum prices, and LPs pressed (sometimes) by recycled vinyl, some (allegedly) with previous record labels mixed in.
Some of the bad reputation *may* be attributable to the noisy and vibration/resonance prone turntables of the '70s. I worked in an audio store in the '70s and we used a dbx expander to goose the dynamics. We always thought the records themselves had been compressed. My opinion now, however, is that the turntables robbed the recordings of their dynamics and phono preamps of the time generally didn't bring out the records' dynamic potential. My all-tube PTP handwired phono stage extracts excellent dynamics from LPs from pretty much any decade including the '70s, and the ones from the '80s will kick you around the room.
As for LPs pressed throughout the '80s (that's 27 to 37 years ago), among the many I own, I've found them to be predominantly excellent. These include the Michael Jackson albums on Epic, albums by Men At Work, Van Halen, Pink Floyd's "The Wall" (released Nov. 1979), Lyle Lovett and His Large Band, Steve Winwood's "Back in the High Life" (1986), The Police, The Cars, David Bowie "Let's Dance," The Nylons' "Seamless" and "One Size Fits All," and many others. I have original pressings of every one of the albums mentioned, and many more from the 1980s. Every one of them could be an audio quality demo record. The dynamics and transparency of many of these are amazing.
I picked up just about every one of these albums at thrift shops or used record store bargain bins for 99 cents each.
One other factor in favor of used 1980s pressings may be that by that time more people were playing records on belt drive and direct drive single play record players with light tracking tonearms. In the '60s most were being played on console stereos with heavy tracking record changer tonearms that also munged the inner grooves. So between the two eras, there's probably a better chance of less wear and damage on '80s-era LPs.
