Yes, that pretty much covers it. Recipe developers are building on work that preceded them that is essentially community property.
Julia Child did not invent French Cooking and did not invent any new recipes. She learned them from others and interpreted them for Americans. Where does one draw a line to determine the point at which Julia actually owns a recipe? It can't be done, so the simple answer is that a recipe cannot be owned or copyrighted.
On
ATK Radio Chris and company did a segment on "The New World of Stolen Recipes" and discussed the issue in depth. Oddly enough, the audio from that show was no longer available when I went to quote from it.