The problem is, that's not really true. There isn't a hard/fast rule that'll get you what you want given the way modern hardware is designed. Run something on a core designed for mobile workloads and that changes vs. one designed for server workloads vs. one designed for HPC. They're definitely not all the same, and the differences will kick you in the rear when trying to simplify.

I do agree teaching people that there are differences, and give them the tools to learn when algorithmic changes are necessary to optimize for the hardware.