The amount of proto-knowledge grows both absolutely and relatively.
Absolute growth of proto-knowledge: As the total amount of information grows over time, so does the proto-knowledge available.
Relative growth of proto-knowledge: As my expertise in a field increases, so does the amount of proto-knowledge for me. The mental framework of an expert consists of more concepts and more connections between concepts. This allows an expert to understand more available proto-knowledge. Also, an expert might have access to more proto-knowledge than a laymen, for example access to certain databases and libraries.