All those are out there in large quantities in my experience since my, I'll write, anecdotal account saw folks purchase them with the intent of carefully storing them and, perhaps for some, the goal of making money off them. I, like most, I imagine just collected them because we enjoyed doing so never really thinking that they would be worth more than a few dollars at some point.
As I have noted occasionally on this board, I purchased virtually all titles of Bronze Age issues, especially DC, including 52 pages issues, off newsstands and comic book dealers in large quantities, typically anywhere from three to six copies of each. Often a lot more. I have all those very securely stored in an acid (edit) -free (so much for 9.8 ) and climate controlled environment in another state. When I retire, one of my goals is to see which are worth submitting to CGC for grading and, subsequently, doing so. Will many be 9.8? I'll see, but I believe most will be CGC graded 9.8 copies.
I also believe that I am very far from the only one that did this. As I noted, many folks that I was a kid with in northern NJ did as I did, some purchasing far more than I. Granted, I don't know if some or many of those folks have already submitted to CGC. However, I do know that two of my cousins that also purchased as I did have not. Their very large, especially Bronze Age, collections are sitting as mine are.
As you know as well as do I, Bronze Age issues are not, I'll write, early to mid Silver Age issues with most, likely, somewhat limited in quantity. Bronze Age issues were collected, including the 52 page DC horror titles in very large quantities with the goal of saving them. Like I noted, I (my two cousins as well) just liked them and wanted to have as many of each issue as possible. I and the others virtually competed to get the best and most copies of each issue. I recall very clearly, like it was yesterday, that the most of the copies were in fantastic condition on the newsstand, especially at the "almost corner store," where I purchased tons of issues, because the owner displayed them flat on shelves since he did not have room for spinner racks (the store was narrow and not too (edit #2) deep with the comic books on the right side in the back).
That is my experience, yours may be different.