hi
USAmericans have no use for dual SIM fones.
the list of countries that do have great use for dual (or triple SIM fones) includes:
China, Taiwan, HK, Macao, India, and all SE Asian countries.
and, of course those people who travel between countries in Asia on a daily basis sometimes.
dual SIM is clearly not going to come from apple, if it needs to be in a physical format.
but don't forget that apple is trying to get network providers to agree to a virtual SIM.
in that case you would have not just a dual SIM but a 100 SIM phone.
the day when apple wants to reclaim that SIM space and use for battery space or something else is coming sooner rather than later. then we will have our dual SIM instead of fumbling around on trains and airports and at borders with changing SIMS.