The i9’s slow supported memory is a product of that being Intel’s 14nm line which uses the same architecture released in 2015. The 10nm core chips use LPDDR4x, just like the M1. The $999 Surface Laptop 3 uses it at 3733 MT/s, just a bit slower than the M1: https://www.anandtech.com/show/14933/microsoft-announces-sur.... That speed of memory is supported on the lowest end 10nm mobile i3, which appears in sub-$300 NUCs available since 2019.
The M1 is a great chip, but that has nothing to do with the location of the memory. LPDDR4x-4267 is a standard memory type. Kudos to Apple for using the highest commonly available speed bin, but it’s a standard speed bin for that type of memory.