The failure rates combined with trying to get what you want is a little brutal. Imagine just grinding for 4 hours, then bringing a whole stack of unknown parts to the NPC with a big smile on your face and then watching the NPC go "oops clumsy me" multiple times. One by one your will breaks along with the modules and then finally you get a success but its not the one you want. Sure you can try and sell it but the majority of the people will want atk or matk modules and the others won't sell for anything. I guess you can argue if someone gets lucky they can make an insane amount of money. If it was something like spend an insane amount to make the one you want with 100% success most people wouldn't really care because you can see yourself go towards a goal. (like edda biolab weapon enchant has a 5000 enchant that lets you choose the one you want.) Seeing stuff fail with no idea when you'll finally succeed is just disheartening.
