Attempting to fit this statement into the history of modern religion becomes difficult. It is easy to see the mass of people in a state of apostasy, but who then are they who would be "save it be a few"? One may easily suppose those few to be those of righteous intent, but surely to do so consigns a great many righteous people who simply lived at the wrong time to a condition of "pride, and wickedness, and abominations, and whoredoms."
Rather than attempt to find among the historical peoples some small few who have remained uncorrupt, this statement should be seen in the light of Nephi' literary technique of couching his future history in terms of Isaiah's themes. In this particular case, Nephi's few parallel Isaiah's historical remnant - the actual body of Israel that would be returned to the land of Judah after the Babylonian captivity.
Because Nephi is attempting to tightly parallel Isaiah, both in language and themes, the inclusion of this temporal remnant (as opposed to the eschatological remnant) is virtually a necessity.