The discovery of fire itself was not progress, but how to use it very much is. They most likely didn't have a "discover fire" specialization in the modern sense but I doubt the one first to create a fire starter was afterwards deligated to collect berries. The discovery and creation of something obviously often comes before the specialization or it would otherwise be impossible to discover and create anything.

>FWIW I don't have a microwave oven. That was just an example. You still know how to use them hence basic knowledge. Seem like this discussion boils down to semantics