I am not sure that I agree that 1 billion is a crashing market unless we have different ideas as to what "qualifies as being considered as part of the market cap"
But if I were to define it, admittedly rather arbitrarily, as that the comic book needs to be a slabbed comic book and have traded on a major auction house website within 10 years, I think1 billion is a fair estimate
Again, I admit this exercise is theoretical. I am mostly just trying to understand the size of what we are dealing with here in this comic collectible hobby.