full width doesn't matter. 90% of the AVX512 advantage is 32 registers, masking, and all the other nice features.
We had Ice Lake and Rocket Lake too, they seem to have disappeared from the collective memory
Their successors had more tangible performance improvements in everyday applications, so yes they were quickly forgotten. Also, it was a reduction in max core count from 10 to 8, intel changes sockets too often, and 14nm+++++.
I have an ice lake laptop with avx512. The problem is that intel only made about 15 of them because their 10nm process was a disaster.