You seem to be refuting claims I never made. I'm simply perplexed that so many people don't know this market exists (as is indicated/suggested by the number of upvotes).
What makes you think upvotes imply people don’t know this sort of thing exists?
I think his comments here indicate that what he meant was he wasn't aware it exists "at scale" in this way, but taking the content of the linked post at face value, it's easy to come away thinking "How did he now know this existed?". It's precisely what I thought after reading his tweets, but before seeing his detailed comments here.