The way RC are viewed fascinates me. For all the reasons stated they are super expensive or could be cheep. Some collectors view all cards from their rookie year as RC's. Others only view the base card from a major set as a RC. Then there is stickers and odd ball cards. Some players if you include odd ball and stickers (and even if you dont) have have RC in more then one year.
I just learned about the carl Yastrzemski debate. I was always under the impression that 1960 topps was his RC then I hear that some think this card is a prospect card and that 1961 is his true RC because he didn't play in the MLB till 1961.
Again it's collectors trying to place either current RC rules or James beckett rules to all cards in all era's. I dont agree with TCDB rules for what they claim is a RC. But that's the joy of the hobby. I can view what is a RC or valuable or is collectable and it does not matter if anyone agrees because it's my collection.
That's the great thing about this hobby everyone gets to have their opinion on what is collectable or valuable or what is cool.
Have fun. N Keep on collecting.