Parchment in real life is made from calf (e.g. young animal) skins, you can't just use an old goat skin as it is not soft and thing enough. VS praises itself to be more realistic and thus it seems logical that parchment can only be made from small hide, as this is likely to come from a young animal. That's my reasoning and why Bookbinders also has parchment only made from small hide.

I expect these recipes or something similar may be added later in the development cycle, but this mod will exist if/until that happens

Ruyeex Base game has at least two recipes for parchment

Idk why it's not even a thing on the base game