I don't think anyone is considering just feeding fodder only and nothing else. I'm not, at least. But fodder can be the base for a completely home made diet with no commercial feed involved. For instance, my chickens will be in my small back yard- not a lot of forage options. So I'll feed them fodder as the base, but also make my own seed/grain mix and ferment it. Plus fresh vegetables and fruits, herbs, bugs I will farm, and raw meats and organs. No need for commercial feed at all. Not everyone is looking to cut back on feed costs, some of us just want to feed our animals fresh, healthy, natural diets. I personally believe that animals fed raw, whole foods are healthier in the long and short term than animals fed kibble/pellets. And especially if I am in turn eating meat or eggs produced from said animals, I want them to be eating as naturally and healthily as possible!
Commercial poultry operations will never use fodder. Even if the cost of feeding it was cheaper, they then have to pay someone to make sure it is watered and growing properly, pay someone to take it out of trays and hand it out to the birds, and pay someone to soak/rinse and start new batches. Commercial feed can be completely fed by automated machines and just needs to be refilled in the storage area occasionally. As you said, commercial operations are all about the $$$... and paying someone to feed chickens costs money.