A CPU produced after a certain date is not guaranteed to have the every ISA extension, e.g. SVE for Arm chips. Hence things like the microarchitecure levels for x86-64.
I don't understand if your comment is ironic. Intel is notorious for equipping different processors produced in the same period with different features. Sometimes even among different cores on the same chip. Sometimes later products have less features enabled (see e.g. AVX512 for Alder Lake).
