Obviously nothing compares to Frank Wilson in respect of Scarcity and Valuation, however what comes after that? I was wondering whether this is worth some reflection, particularly since some items which may be considered "played out" and were relatively common in 70's and 80's are still in demand and commanding high prices. e.g. Frances Nero, always a great tune but wasn't difficult years ago : https://www.popsike.com/php/quicksearch.php?searchtext=Frances+Nero&thumbs=&