Discounted Flight

I keep getting these emails from the airlines I use the most, advertising their specials with low fare in economy class. Okay, that may be great for occasional travelers but I always think: Aren't economy tickets ALREADY cheap enough?? I mean an economy ticket on a long haul is normally not even self-sufficient. An airline actually finances the flight mainly with cargo and with premium tickets in first and business classes. Maybe it's just me but as somebody who flies an awful lot and pay premium fares all the time (I know - it's my personal choice, nobody forces me to do that) I always wonder why they don't make such offers for their customers who pay the expensive tickets. They seem to aim at occasional travelers, cold customers if you want. Would it not be more efficient to please the premium customers who give the airline repetitive business?