@rvpiano If it’s any consolation, my experience is much the same as yours. I have many old albums which have been meticulously cared for over 50 years…most of which simply sound flat and thin. Recording quality for most popular consumer vinyl was relatively poor especially for pop/rock music.
I’ve reached a point where I only buy new vinyl for that reason. And it’s still a gamble. You can clean those old records all you like. It won’t change the recording quality.