> I haven't dug into the post-2015 phones yet to see if there are any other natural boundaries that will show up ... I suspect TouchID will be the next one we

> I haven't dug into the post-2015 phones yet to see if there are any other natural boundaries that will show up ... I suspect TouchID will be the next one we hit, but that is going to be at least four years off because iPhone SE #2. The neural engine may be a feature cut-off after that, where there are just too many features and services being run on device which can't be done on older hardware. Other than that, I suspect Apple will still institute a vintage/obsolete lifecycle for phones - just choosing to drop support for phones where the hardware hasn't been sold in a certain amount of time (say five years), official replacement parts like batteries are no longer being made, etc.