Correct, in D3, you must pay gold to upgrade your blacksmith, and then you must use speciality items that are only found in certain difficulties, effectively putting a cap on how far you can upgrade the artisans within a given difficutly (obviously AH bypasses this). Blacksmith is at the moment, worthless. Jeweler however is mandatory to upgrade, because the last 6 gem tiers do not drop, so you first must upgrade the jeweler to craft up, and for last 4 tiers, you must get their designs for the jeweler to use (one time requirement, item drop, in lieu of upgrading, since he will be max upgraded). The numbers are already known, it will cost millions to get last tier gem (starting with highest dropped gem, you will need 243 Tier 8 gems and it will cost you 8 million gold to get final tier (tier 14) gem after your done crafting all the way up. Probably will not see top tier gem on AH for a while since people either don;t have them, using them. By the time they roll around, I fully expect them to sell around 15-20 million a pop.