Q&A: Migration to non-Muslim Countries

Is it permissible for a person to reside in non-Muslim countries with all its temptations that confronts the person on the street, the school, the television and other media while he has the ability to migrate to a Muslim country although that transfer would cause difficulty in residence, loss of material wealth and comfort, and constrain the worldly aspects of his life? If it is not permissible to remain in such a country, would his efforts in propagation among the Muslims (reminding them of their obligations and encouraging them to refrain from haram) change the rule for him and allow him to remain in that country?

A believer residing in Europe, America and other similar countries feels estranged from the religious environment in which he was born and raised. Neither does he hear the voice of the Qur'an [recited from mosques] nor the sound of the adhan coming [from the minarets]; and there are no holy shrines, and their spiritual atmosphere, that he can visit. Is leaving such an Islamic environment of his country and its positive aspects considered "loss of faith"?