Islam v west or kafir or what?

[MSalman]

If Muslims subscribe to the view you set out here, would the solution then be for all Muslims to live in Muslim countries and all non-Muslims live in non-Muslim countries?

no, I did not say this or implied. I am simply saying that there lands of kuffaar (yours) and there are lands of Muslim (ours): you rule in those lands and we rule in our lands.

And is it not the case that Muhammad foresaw this problem and commanded that Muslims must not live amongst the muskreen?

not exactly, this issue is more broader than you simply put it. Frankly, it is out of my scope.