You cherry-picked the top-end CPU, which obviously has the highest multi-threaded performance. The 6-core and 8-core Ryzens are drastically behind Intel in productivity.
"Drastically behind"? This is total nonsense. Have another cup of coffee and check the reviews.
1. 12-core 9900X is on par on average in applications with 20-core 265K
2. 8-core 9800X3D is 4-5% faster on average in applications than 14-core 245K and only 12% slower than 20-core 265K
3. 6-core 9600X is only 13% slower on average in applications than 14-core 245K
12-13% is a "drastic" difference on small core count CPUs, indeed...
The Ryzen 7 9800X3D establishes AMD as the leader in gaming performance. This Zen 5-based X3D chip is not only fast, it also comes with full support for overclocking. Besides gaming, application performance is considerably improved over the 7800X3D, but that comes at a price.
www.techpowerup.com
The 9600X was still a 6-core CPU, the generational improvement was abysmal, but they still charged almost $300 for it.
You started with dubious core count narrative, now you introduce other variables, such as uplift and price. You need to decide what your narrative is actually about, because you are now suddenly spinning several balls in the air, not just core count.
As a consumer you should be advocating for progress. We had 4-core Intel CPUs in the mainstream for almost a decade when AMD had nothing. It's time to make 8 cores the baseline.
I always advocate for progress, but 8 cores does not need to be "the" baseline because consumers have complained for a long time that entry CPUs are not that common. There need to be entry CPUs too, such as R5 9600 or R5 8500G, and those do not need 8 big cores. With Zen6, 8 cores might become the new entry point CPU, but we will need to see how this pans out. I still prefer to see 6-core SKUs too, so that devices like NAS are not artificially more expensive, where more than 6 cores is not needed to run such a product.
However, as published recently by Passmark, both AMD and Intel CPUs have flattened in performance uplift with the last generation of desktop CPUs, excluding X3D, somewhat. So, yes, it looks like we have reached the plateau with current architectures and features on retail CPUs, but this is not an analogy for "4-core era". Zen6 and Nova Lake should bring progress in several segments and features beyond higher core count. Both companies push forward, as they should.