One person gathering 15 ingredients from 5 different locations and using them to create something themselves isn't really how the game is supposed to work IMO.
You live near the Muse fruit. You know it's valuable. Every time Muse fruit is up, you gather it. You then post it on your local broker. Someone far away is making potions that use it. They perhaps gather 5 of the ingredients they need for their 15 ingredient potion themselves because they are convenient. 5 they buy from allies or guildies that do more travel than they do. And for 5 of them including your muse fruit, they just put up a buy order on the local broker.
I'm a trader. I see that Muse Fruit sell near their source at 40 gold per X units. And you put in an order for 50 gold per X units. I see some other Muse fruit orders and orders for different goods that are cheaper in the location I'm at that will allow me a profit if I safely get them from my current location to your area. I load up my pack animals and head that way looking to make a profit.
Here is the thing. Every single mechanic that makes it easier for people to just go get the Muse fruit themselves, the less likely I am to conclude there enough volume and value of goods to be moved to actually decide to become a trader. If nobody becomes a trader, then you really WILL have to go get all 15 ingredients yourself.
You live near the Muse fruit. You know it's valuable. Every time Muse fruit is up, you gather it. You then post it on your local broker. Someone far away is making potions that use it. They perhaps gather 5 of the ingredients they need for their 15 ingredient potion themselves because they are convenient. 5 they buy from allies or guildies that do more travel than they do. And for 5 of them including your muse fruit, they just put up a buy order on the local broker.
I'm a trader. I see that Muse Fruit sell near their source at 40 gold per X units. And you put in an order for 50 gold per X units. I see some other Muse fruit orders and orders for different goods that are cheaper in the location I'm at that will allow me a profit if I safely get them from my current location to your area. I load up my pack animals and head that way looking to make a profit.
Here is the thing. Every single mechanic that makes it easier for people to just go get the Muse fruit themselves, the less likely I am to conclude there enough volume and value of goods to be moved to actually decide to become a trader. If nobody becomes a trader, then you really WILL have to go get all 15 ingredients yourself.