A lot of people, especially outside the smoking/BBQ world, prefer leaner meats these days and the point is pretty fatty. Look through recipes for corned beef or other non-smoked briskets and often people are using smaller portions and often the flat. Not always of course, but often enough.
And really, pricing and availability is often a good indicator of what people want. Stores make more money stocking things that are in demand than they make stocking things nobody's buying. :)