I get what you mean.
But sorry, that's not how it works. You buy the 10,000 arrows - when they run out, they run out. You can't refill that one-slot quiver with arrows from the Blacksmith. Until then, they only take up one space in your inventory. And think about it... how long will 10k arrows last you? A decent amount of time - that's like 40 stacks of 250 arrows each. And they don't even cost that much. You could definently use the space for something else - god know that carrying all those arrows around is definently a con of being a Bowman.
