Individual reactions vary, but it's safe to assume that an army lacking food will be at a big disadvantage when compared with an army with enough food. It's also safe to assume that the longer the war, the more tiresome it gets for the soldiers - war exhaustion effect is currently non-existent in vanilla HOI3. Germany feared WWI replay for a reason.
Instead of obliterating IC capacity, strategic bombers could increase war exhaustion in addition to standard NU hits. IC, on the other hand, should get harder to destroy the lower it is in relation to maximum value - strategic bombing campaigns were very intensive both in Germany and Japan, but they didn't destroy industrial potential of those countries, only hampered them.
For me, terror bombing is abstracted in form of NU hits, but food resource would still be very beneficial for gameplay.