@Olejniker,
Quote:Emic and etic are terms used to refer to two different kinds of data concerning human behavior. In particular, they are used in cultural anthropology, to refer to kinds of fieldwork done and viewpoints obtained.
An "emic" account is a description of behavior or a belief in terms meaningful (consciously or unconsciously) to the actor; that is, an emic account comes from a person within the culture. Almost anything from within a culture can provide an emic account.
An "etic" account is a description of a behavior or belief by an observer, in terms that can be applied to other cultures; that is, an etic account is '"culturally neutral". (Wikipedia)
The reason I quote this is because you are considering the question from a etic perspective. It is one thing to be 'above', as it were, the three great traditions and think about them from the perspective of one who might not have any kind of stake in any of them, or in whether they are true or not, or whether there might or might not be any real consequences in believing in them or being part of them.
From an 'emic' perspective, the question looks very different. In other words, for a Jew, the relationship with Islam and Christianity, is redolent with all kinds of meanings and subtelties in historical memories which it is very easy to overlook or diminish as an outsider. The same could be said for each. Within each community, there are those inclined to emphasize the commonalities, and those inclined to emphasize the differences. And, when you think about it, even within these communities, there are tremendous schisms and divisions (Sunni-Sh'ite, Protestant-Catholic, etc) which again reflect the internal complexity of such relationships.
I think with respect to all of the actual communities of the faithful in these various religions, the idea of a commentary from the outside along the lines of 'don't you all worship the same God' would be met with 'yes, but...' followed by a considerable amount of qualification, explanation, exegesis, and so on, most of which we would probably find very hard to understand without quite a bit of hard study.
And that, I suppose, is a 'meta-perspective' and something to bear in mind when considering these questions. It ain't nearly so straightforward as it looks.