It depends on what you buy. For example, Aloha's cordyceps is 5X more potent than wild cordyceps in Tibet. Thus, one capsule is over 2.5g of dried herb.
At my worst, I took 6 pills a day -- no ill effects, but not necessary, either. From what I've heard, even higher doses are just too strong for most people. At least when it comes to Aloha.
Also, I don't know if cordyceps was ever eaten as a regular food. I know it's cooked with duck to increase potency of the cordyceps, but again, I think that's for the therapeutic value.