iPhone/iPad 16GB RAM + 64GB hardware local LLM ROM. Apple can phrase it as both a benefit and a reason to upgrade and reduce its costs over suddenly bumping RAM by 400%.
Out of all the hardware manufacturers, Apple is the worst candidate to pin planned obsolescence on. Its devices are supported longer than its competitors, and they get better at lasting longer over the years.
I don't know if mask ROM even exists any more or what its density would be. Realistically your choices are DRAM or flash and flash will probably never be fast enough to hold model weights.