It's the fact that despite being power hungry and hot, people are still buying 12900K. It's the number 6 best selling CPU on Amazon. I mean, really??? If people had more sense than money, this spot should have been occupied by the 12600K and the 12900K should have been in the top 20, not the top 10.
I wouldn't use the Amazon Best Seller CPUs as example for poor AMD sales, it's the EXACT OPPOSITE:
Your opponent hitting themselves repeatedly in the face with a frying pan is NOT threatening, it's just weird. Intel had an arguably great architecture with Golden Cove but the end product has had several problems that hampered adoption. From development decisions around the hybrid mix on desktop, to marketing decisions around default power limits and more importantly pushing for Windows 11 (which backfired in a grand way), and finally to platform change decisions around socket compatibility, DDR5 & DDR4 mix and most importantly motherboard production costs, everything conspired to delay consumer response to Alder Lake.
They should have taken AMD by storm, yet all they managed was the Amazon status quo from above. The 12600K as you put it should have been not above 12900K, it should have been in top three. The 6+4 chip from Intel is the best blend of value & performance in years, yet it failed to become an instant win in every chart. Let that sink in, look again at that Amazon chart.
The 12400, one of the most welcomed products on this forum, is number 17 on that list. It matches 5600X in just about every workload, has an iGPU and costs less. Number 17!!! Just because you have the better product does not mean it will sell itself. AMD learned this the hard way, it's now time for Intel to realize that childish marketing proposals such as PL1=PL2=250W is not enough to regain mind share.