"A lot of collectors probably have been hiding under a rock the last 3 years...tons of people left the hobby in the 1990s and haven't come back."
True, but anyone who was collecting in the 90's would know that the Hulk 181 has value. I find it hard to believe that someone sitting on a hoard of NM copies of a book worth $200-$300 wouldn't continue to track its progress, especially after the media exposure this character has gotten from the cartoon, and the movie. Even if they weren't actively collecting, if they hoarded this book, it's likely for an investment. And what kind of an investor wouldn't check the status of his investment at least every couple of years. It's quite a stretch to say that this person wouldn't pick up a Wizard, or look in an Overstreet every once in a while. And if they did so in the last 3 years, they would know about the increase in value, and of CGC.
"I've seen that Neat Stuff, for example, has huge stacks of pristine copies of Bronze Marvels in inventory and I'm quite sure they don't even know everything they have."
But with their knowledge, I seriously doubt they would have a hoard of a major key in pristine condition without knowing about it. That's pretty far fetched. "Some 70's Thor" is quite a bit different from a Hulk 181. If they're so busy that they don't even realize they're sitting on a hoard of NM Hulk 181's, they should get out of this business.
why couldn't a shrewd speculator have stored their Hulk 181s in a smart fashion?"
So if these speculators are so shrewd, why would they let years pass without checking up on their investment?
"Well, I don't know about you, but if I had 100 hoarded Hulk 181s, I sure as hell wouldn't let anybody know about it!!! "
I agree with that.