My first record store job was in 1970-1, and let me tell ya, we had to return a LOT of defective new release LP’s that year, whole batches of them. LP pressing quality has ALWAYS been an issue. That’s one reason I and others started buying import LP’s in the late-60’s/early-70’s. British pressings ALWAYS sounded better than their U.S. equivalents. German ones too. Japanese LP’s were very well made, but sometimes suffered from odd equalization.
"Pure junk from otherwise respectable audiophile company"? For instance? I’ve never received a junk LP from Acoustic Sounds (Analogue Productions), Speakers Corner (made in Germany. I think junk is illegal in that country ;-), MoFi, or any other audiophile company. Yes, sound quality varies, but that is more a matter of the original recording than the pressing. Again, for new LP’s, look for those pressed at QRP, Pallas, Optimal, and RTI.
"...junk records of bad quality will rarely appear there." (the used market). You cannot be serious! I don’t know where you’re looking for and/or finding used LP’s, but LP condition grading is a major---no, THE major---element in the collectible LP market and business. Near Mint condition records comprise maybe 5% of all the LP’s listed on Discogs, VG+ another 15%. Below those grades, all bets are off. Most used LP’s are "junk":, but that’s because of user abuse, not pressing quality. When I peruse the bins at my local used LP shops, for every one record I find in condition good enough to consider buying, I see and reject about ten.

