I actually agree with you, as evidenced by the fact that I got all my degrees in that area.

Didn't know that.

I think experts tend to think what they are doing is the most important thing.

I think there is a definite tendency that way, for the obvious self-selection reason, but I don't think the tendency is necessarily that bad. A fair number of my professors did do a little spiel justifying the value of their particular field, but I don't remember any of them which were that grossly out of whack in their assessment - eg the cognitive psychology prof argued it was important and interesting, which I don't disagree with, but he didn't say it was 'what was really important'; the philosophy professors generally tried to justify the field, but they were satisfied if you saw some value to philosophy at all and didn't try to claim it was the most important field, etc.