Why ‘is there’ omitted in sentences?

Question

I’d like to know why ‘is there’ is omitted in the following sentence with grammatical explanation:

Why the widespread imbalance in their interests and expectations?

Answer 1

Nothing has been 'omitted', it is just a different way of saying the same thing.

You expect it should say:

Why is there a widespread imbalance in their interests and expectations?

Notice that I've used the indefinite article, whereas your example uses the definite:

Why the widespread imbalance in their interests and expectations?

I imagine that the wider context of your quotation has already established a few things, such as who "their" refers to; likely it has also hinted towards an 'imbalance'. So, having established which imbalance you're talking about, you can refer to it with the definite article - the (aforementioned) imbalance.

There's no need to keep repeating the same things over and over. Consider this exchange:

-Why are you wearing my coat?
-I was cold.
-But why my coat?

There's no reason for the person to repeat "why are you wearing..." so instead they just ask "why [x]" which is not dissimilar from your example.