> For instance, "peanut cake" is a byproduct of peanut oil manufacture. It's what's left over after the oil is extracted, and it's ~35% protein, full of vitamins, and almost as cheap as dirt. I don't see how something made in a vat can compete with that.

For animal feed, perhaps. For human consumption, at a minimum, it'd be nice to have a variety of alternatives, such as for people who can't eat peanuts.