I wonder if it would be possible to make an NPC that actually reads your character's stats and then has an output accordingly. So the NPC would have the same rates as the alchemist using it.
Then the alch gets to stay in business and do less clicking! I very much doubt it's doable though :x but I know next to nothing about scripting so I could be wrong.
More realistically, I guess you could just give the NPC a set rate on mats :x and said rate would be a bit lower than an actual alchemists (To be inefficient and remain fair to the alchies at the same time.)