I'm going to stick my spoon in here.
I'm also a veteran with lots of vinyl and having bought new, and always played on decent TT's with their respective decent tone arms, they sound like day one.
PVC has a property that helps prevent it from getting damaged so easily, it is flexible, the grooves can be deformed - in microns - when played (they even get hot, you have to avoid repeating a song, let them "cool") but they return to their place. Of course, if you play them with the tone arm my father-in-law used, 5 gram weights VTF or more and a worn sapphire needle, that's damaging. But even so, I inherited several of the LPs he used, and I will tell you that what most spoils a pleasant hearing is not the hypothetical loss of treble, but scratches. That's one of the reasons that always annoyed me, even the "pops" and "surface noise" on new vinyl!
The pops are lumps of PVC in the form of "mounds" and the surface noise...... well, you would think that around here (we are South Americans, like Africans, etc., we belong to what was called the third world, Do the older kids remember that phrase? ) So, in times of scarcity of foreign currency to import PVC, the record companies recycled used vinyl, (I'm talking about prestigious companies, Phillips for example) but, "gossip" told me that they witnessed how the labels were removed with grinding stones, of course, sometimes particles of the "ground" paper leaked into the paste.....Can you imagine what happens when the needle runs into one of those residues that is melted in the PVC? Well, you can have the most sophisticated system in the world to clean vinyl, (ultrasound?) but the noise will be there forever.
They are not "delights of married life" to live with that, especially feeling cheated. You asked for your LP to be changed and you could be lucky or not, many times the replacement was worse than the one you left with the merchant. Which of course did not go "in return" to the record company, but returned to the corresponding on the display box ...