Embedded devices are likely to be 32-bit for a very long time yet. I'd consider 100+ years to be a reasonable number!
64-bit devices are much more complicated (bus size, peripherals, part count) and therefore more expensive. If your entire task fits in a 32-bit space there is little motivation to use a 64-bit core.
It won't on full SoC devices but most ARM embedded devices of that sort have all sorts of peripherals which are bus connected so the bus will need to be external.
64-bit devices are much more complicated (bus size, peripherals, part count) and therefore more expensive. If your entire task fits in a 32-bit space there is little motivation to use a 64-bit core.