OK, I see where you're coming from on this. For you, there a certain element of the thrill of the hunt! It's the same thrill collectors of anything vintage get when they make great finds and get good deals. I can dig that entirely. There's history not just of the manufacture, but of the ownership, uniqueness in that fewer examples exist...and naturally, the quality of what was made.
I could see one defining the period before and including the 1950s as historically significant, and having visually beautiful cards that couldn't perform very well but were dead-on gorgeous. Going from there into the 1960s, you have the introduction of quality innovations - now you have great looking cards that perform well; a true golden age of the playing card. After that, heading into the mid-to-late 1980s, companies in general started to forget what quality was and churn out crap, figuring people would buy it anyway as they have all along. This was also a turbulent period for USPC - it changed hands a number of times, if I remember the company history time line. Card quality suffered - it was a dark age. We're now in the midst of a period of upheaval in the market, with new technology in the form of CGI and CAD, the advent of Magic Finish and the custom deck - call it a Renaissance, if you will. Perfect? Nah. Not even close. But better than it has been since any time after the Golden Age.