As expected, two persons are using past history try to speculate Apple will be late to adopt LPDDR6. And they are ignoring that how aggressive Apple is adopting LPDDR5 in MacBook. Apple was the first vendor to use 512-bit LPDDR5 and until today, no OEMs are able to do that.
iPhone Pro lineup going to get even more Pro features; one of them I think would be 12GB LPDDR6 support. With extra memory bandwidth, Apple going to add at least 2 more GPU cores thus pumping FP32 to around 3TF. Meanwhile, I suspect A18 would be like N3E version of A17 Pro featuring 6 GPU cores with 8GB LPDDR5.
Based on release timings, the rumored 8G4 (supposedly launch at Q4 2024, same timeline as iPhone 16) supporting LPDDR6 might be true cause 8G4's GPU performance is rumored to be around 35% faster. Guess what, A18 Pro's GPU also rumored to be around 38% faster.
Another advantage of LPDDR6 is cost and capacity. Most of the DUV-based LPDDR5/X die is using 16Gb (2GB) die size, thus in order to have 12GB, the memory chip have to use up to 6 dies. With EUV-based LPDDR6, 24Gb (3GB) is the standard thus Samsung only needs 4 dies to build a 12GB memory chip. It seems Apple going to use even bigger die size of 32Gb (4GB), that's means Samsung only needs 3 dies to build 12GB LPDDR6 memory chip. And that's how Apple able to fit 256GB memory in upcoming M4 Max. More on M4 series later.