I think that there seems to be some mixing of facts. A 150 grain .284 bullet and a 150 grain .308 bullet are the same amount of projectile. The fact that one can create a larger ENTRY hole isn't really telling much. Bullet construction and velocity mean a heck of a lot more than the diameter, especially the minimal difference between .284 and .308. Basically we're talking about 7mm and 7.5 mm (approx).
There is such a small difference between the .280 and the 30/06 I wouldn't even bother with choosing between the 2. If there were 2 identically equipped rifles except for chamber, one being 30/06 and the other being .280 I would be happy to be carrying either afield.
There is no question though, availablility of ammo is a key consideration to those that don't handload, and therefore marketability is definitley affected.