They're only valuable because everyone threw theirs away! Even then, the market for stuff that Boomers find valuable will never be what it was. If you held on to anything past 2008, whether comic books, baseball cards, or Fender guitars, you missed out. That train has left the station. The upcoming Millennial and Gen-Z folks will never place much value on any of this stuff and as Boomers start dropping like flies, estate sales are going to be full of old comic books. Few people are going to want them.
Dunno about that. The Marvel movies have had a significant upwards impact on the price of comics from the previous era. If you have an original #1 of a comic that Marvel makes into a movie, you’ve just been enriched.
That's shaping up to be true. I was an avid record collector for decades but all of that music is instantly available to stream. While people of my generation appreciate the cover artwork and liner notes, the younger generation couldn't care less. Ditto for books and I have a lot of those as well. Everything is so easily accessible online that there's nothing special about having the physical media anymore.
Don't be shortsighted. Things that were collectible in our grandparents time, are still collectible today, as they will be tomorrow.