Most of the Intel cache partitioning things were driven primarily by Google. The holy grail was to colocate latency-sensitive tasks with bulk background tasks to increase cluster utilization.
I guess technically CAT and RDT are not ISA extensions because they are managed by MSRs. I was thinking of aspects of BMI, but I am sure that large-scale buyers had input into things like vector extensions, PMU features, and the things you mentioned as well.