Idk, after taking a look at this video, I'm pretty impressed with his thorough analysis:
Amazon vs. eBay prices (current and sold) and sales velocity
How many sets are currently for sale on those channels
Historical discounts offered throughout the set's lifecycle
Best guess on quantities produced based on current availability/observation across channels
Philosophical take on the future buyer's motivations to buy this set
I'm not saying others don't provide this information, but he's bringing all of these variables together for a complete picture to make your best guess.
We might disagree with his conclusions, but we can't discount all of the underlying variables he brings to the table to make his decision. This dude does his research and we can leverage that research to make our own decisions. And, he's humble, consistently saying "This is my take, yours may be different based on the provided information".
I'm happy his channel was shared on BP. I subscribed, but would never do his Patreon lol.