First of all, Rabbonim have the right to disagree. If you live in a place where your Rov paskens a certain way, you’ll listen to his psak. If you then move to a different place and have a different Rov, you’ll listen to him. I don’t know why that’s so hard to understand.
It is rather difficult. The halacha does not change from place to place. Now I agree that one should be Machmir to follow the minhagim/psakim of the Rov in a specific location, but that is due to Kavod, not P’sak. Besides, that would mean that depending on where you were (Mea Shearim vs. the Gush), you would or would not have a smartphone (as the Rov in the Gush is not the same as that in Mea Shearim).
Second of all, the Gedolim on the two sides of the ocean always recognized that what works for E”Y doesn’t always work for the U.S. and vice versa. Therefore many of their psakim tend to only be mean for local consumption. I think that’s pretty easy to understand as well.
I agree, but once again, you are just proving that the issue is not Halachic. Halacha would not change depending on what side of the ocean you live. Hashkafa does.
Having said all that, chances are the Gedolim in the U.S. would pasken the same way as the ones in E”Y if they thought the tzibur would listen to them.
You’ve proven my point once again. If it was Assur Mamash, there is no way that anyone would be Mattir.