But Bullzdozer was never the best. It was never good at all.
Much of the HEDT market is people who want to buy the best: who need PCI-E lanes for multiple high-end GPUS, who need cores for edge cases, extreme gaming/streaming, benchmarking, etc. A 9900K/KS will still see gains over anything AMD has even at 1440p/165hz, btw - a target at which a high end 2080Ti or Titan can shift the bottleneck to the CPU.
There is a very significant chance that the 10980XE will be the go-to chip for the likes of 3DMark, gaming benchmarks and the chip that the GamersNexus/Jayz/whatever of this world will use to extreme cool and try and have their overclocking battles. It'll have more cores than the 9900KS, will reach similar clockspeeds under expensive cooling (e.g. chillers) and the mesh frequency can be overclocked considerably to catch up to ringbus. Threadripper 3 will win on Cinebench multicore and Blender but is unlikely to have the latency to compete against the 10980XE in the gaming world.
As someone whose had a 7980XE since the day it came out, it is disappointing that the 'top chip' nearly 3 years later is basically the same chip at half price. Sure I'll probably buy one just to see if it's binned better but I'm buying the same chip twice. While they've made massive strides in price/peformance in the mid-range and low-range, I still don't anticipate anything from AMD changing the pecking order at the halo end. When Kingpin turns up to overclock something in an article, he'll probably use a 10980XE and nothing from AMD will be able to compete with the result. This is overclockers uk, after all