I go to a multi estate auction every month. There are always box fulls of comics, cards, beanies, barbies,trains,stamps, for sale. Some stuff goes for a decent amount, other stuff you can't give away. I've loved comics for 40 years. I learned to read, i think, by reading comics. But I would never invest in comics. Seems like a crime to buy a comic and immediately put it in plastic to "preserve" it. I have to admit I love the art. I can walk through a museum and feel nothing, but a lot of comic art, blows me away, especially Dr Strange early art. How do you make a character all dressed in black, visible in the shadows. How do you represent the character "infinity". How do you show the power and fury of the Hulk. Comic book artists are geniuses in my opinion. They do have digital comics now, you can read thousands of comics on your computer. I don't think reprints are to blame. Everyone knows a reprint is worthless. I've been suckered into buying special editions, holographic editions, number ones, only to see them on ebay for a dollar or 2. I think the economy and ebay are responsible for comics losing value. Something is only worth what someone else will pay for it. Guess what, moneys tight right now. Also, if you wanted a special edition, you were at the mercy of local comic shops. With ebay, you have thousands available of anything you want.
My parents always collected european stamps. Now they are practically worthless. They always said though, don't buy american stamps. America is so large they print millions, which makes them only face value. Thats happened to baseball cards and comics during the 90's, and today. I'd love a first edition spiderman, I'm not paying thousands for a comic book. I would love a MM Pin, but I'm not paying thousands for one.

baseball cards got creative and introduced die cut and other nonsense. It worked for a while. Same with comic books. I bought one spiderman with a gravestone shaped cover on it because aunt may finally died. I think there are a dozen different issues where aunt may dies. Then I bought all 4 "special" issues of spiderman with the holographic cover. I think they're worth a dollar each still. I see the varient comic or valient comics for 5 dollars a box of 100 at estate auctions. Original comic art has held value. Its almost incredible since there must be hundreds of thousands of example of art out there.