Earlier quoted context omitted.
The main selling point for Intel isn't speed anymore. Intel still has superior performance counters and debugging features. Mozilla's rr (Record and Replay framework) only works on Intel for example, and Intel vTune is a very good tool. AVX512 is also an advantage, as you've noted. There are other instruction set advantages: I think Intel has faster division / modulus operator, and also has single-clock pext / pdep (…
Even if you do, in most cases you won't use them on all your workloads. This means not all your boxes need to be Intel.
Lets say production is 50% slower than what's tested in staging / developer test cases. Is it the data in production that causes this performance loss? Or is it hardware differences?
If you are using Intel tools to debug performance problems on developer / testing stages, you probably want to keep using those Intel tools in staging / production. There are enough cache differences and instruction-level differences (speed of "division" instruction. PEXT vs PDEP. Cache differenches, branch predictor differences, TLB differences) between the chips.
Intel has interesting optimizations: an Intel Ethernet card drops the data off in L3 cache (bypassing DDR4 RAM entirely). These little differences in the driver / motherboard / CPU can have a huge difference in performance, and complicate performance testing / performance debugging.
If you are deploying to AMD hardware for production, you probably want to be running AMD hardware in testing / developer stages as well. You want all your hardware performing as similarly as possible.