I used to feel the way you do, but as I have run more SBR campaigns my feelings have changed. SBRs are just fine as they are. While statistically they should be about a break even proposition I find they are not. For example on paper, an Axis SBR campaign using 3 bombers per turn should do 15 IPCs damage per turn to Russia. While the Axis powers each loose a bomber every other turn, resulting in an equalization. I find that the Axis powers can afford the IPCs spent to procure the bombers. However; a Russia with little or no income is all but dead and praying the dice can hit the bombers or the Allies can get units to Moscow in a hurry.
People should keep this point in mind. It is not how much you spend versus how much damage you do, within reason. It is where the damage to your opponent is done. And I feel that applies to much more than just strategic bombing.