I see statements like this from time to time, and I can't help but laugh. Are you flying Qatar only because you thought that the last minute upgrade cost was lower than it is? That's the only reason?? And on your next trip, when the QR fare is 20% less than the other carrier on the route, you still won't fly QR, right? Because Qatar Airways has lost you as a customer.

You're presumably upset because you wanted to fly in business class but want to pay less than what QR charges, right? If you really want business class, then buy a business class ticket and pay for it, like so many other people do. Otherwise, you take your chances. Sometimes the last minute upgrade will be less, sometimes more. QR isn't in business to give you an upgraded experience at what you think it should cost. It's in business to make money.