In my experience, despite the cards having value in a book, there's just no interest out there in buying baseball cards. Obviously rare, high-dollar cards are an exception, but that isn't Topps from the 70s or Topps/Fleer/Donruss from the early 80s.
I had tens of thousands of cards that I moved any number of times. I finally gave up trying to sell them and tossed them in 2016 during a move.