Some guitars are ridiculously overpaid so I don't think you can say anything about Mark's popularity. Let alone prove anything.
David Gilmour's black Partcaster which from what I can tell was modified a lot went for almost the entire yield of Mark's auction. He'll generate more with the signed Teenage Cancer Les Paul, but that's cheating.
Mark's guitars, on the other hand, are meticulously crafted and constructed, most of the time with his exact specifications in mind. And then being kept in pristine condition with care, barely showing any playing wear. And used on some great recordings, both video and audio. I don't know what's overpaid where and why one can still argue that Mark is popular when he's not.
You can bet even if Mark put out his other iconic guitars, like the National, it would also generate the "meh" outcome. It would sell for 400 grand just like Pensa.