You're missing the forest for the trees. Cast iron pans retain heat better than aluminum pans because cast iron pans are 4mm thick and aluminum pans aren't 6mm thick.
(Also it does retain heat better. [EDIT: by thickness, not by weight. The comment below is also correct.])
https://www.centurylife.org/heat-retention-myths-and-facts-d...
In the end, it didnt cook that much better than my All-Clad D7. So I just stayed with that. But I have never cooked with anything so brimming with heat and ready to pour it into absolutely anything that came into contact with it.
https://www.makeitfrom.com/compare/6061-AlMg1SiCu-3.3214-H20...
For most day-to-day cooking where you're ingredients are in direct contact with the pan over a burner (sautés, searing etc) heat retention can actually be bad (it's difficult to adjust the temperature). For specific tasks, cast iron excels, that's why you don't see a lot of copper deep fryers.
(This is mentioned in the 2 experiments that person runs in their kitchen that you posted)