I suspect that there will be a penalty in battery performance in older iPhones vs. newer iPhones due to increased load on the Neural Engines offloading the CPU. So, while more Neural Engines "should" provide new benefits, there is a strong incentive to adjust basic/old functionality code towards being clearly detrimental to the performance older iPhones, incentivizing customers to buy a newer phone🤔 That is, at some point you are forced to upgrade iOS, making your iPhone slower simply due to code switching and NOT due to newer, more demanding functionality.