I can't speak to softness in pricing for the Colan Hulk 11 splash, but $9K seems like a fairly strong price considering Colan is not an artist associated with the character. Regarding the $15K asking price by the seller, well, folks can ask whatever they want. Some prices are grounded in reality. Others, not so much.
The Sienk Moon Knight pages did not sell low. Based on prior sales results, I would say they went for fair prices in comparison to prior results for similar pages
Agreed the Anderson Xmen page went strong
Byrne Wolverine #21 cover - never thought it would touch $50K. Maybe $35K at most
J.Scott Campbell covers were all over the map, and with only one or two exceptions, sellers lost money
Kupperberg Spec Spidey pages...agreed, they went low and were a good deal
Perez Back Issue #1 cover went very, very cheap. Congrats to the new owner