You wouldn't know what those are just by seeing them on an ingredient list either. The issue in your analogy is I am not there to hand them to you. It's just the recipe telling you what to do with them. You would need to know what they are and where to find them without a store to go to and pick them up.
Just because you can cook stuff doesn't mean you can cook something you've never cooked before using a list of ingredients you don't have and cannot buy. You would need to harvest and prepare those ingredients first. Do that without knowing where to find them, how to harvest them, how to prepare them, and how to preserve them long enough to get them back to your kitchen when you don't even know what they are.
The dwarven smith example has an adventure to complete to get the ingredients. During the course of that adventure the dwarven smith will need to somehow find the ingredients and recognize them, make sure those ingredients are in a suitable condition for use, and be able to transport those ingredients in a way not to ruin them as examples of what one might expect. Proficiency in arcana is not required to make INT checks but adding that bonus improves the likelihood of successfully getting those ingredients in order to craft the item.
