No complaints about the label overhead. It's only fair they make back what they put in. I don't think their profit should be higher than the artist royalties though.
And I don't understand how the retail overhead of stocking a CD is so high either.
On the marketing/promotion front, that's not just advertising. That's interviews (travel to/from, phone calls etc), reviews (sending out CDs), in-stores/promo tours etc. Advertising's just a small part of it.