Everything you said about memory space & bandwidth is 100% on point. However: arm arch 32 has 14 general purpose registers (including the link register). arm a

Everything you said about memory space & bandwidth is 100% on point. However: arm arch 32 has 14 general purpose registers (including the link register). arm arch 64 has 31 general purpose registers (also including the link register). I also doubt there are real power savings in modern out of order processors. The few transistors saved in the register file and ALUs are just dwarfed by everything else. Heck, look at how much of a modern soc like the M1 is used by the compute complex compared to everything else.