Yeah, Magic: the Gathering is not a suitable basis for analogy, except for drawing a distinction between spells (things you do) and abilities (things your stuff does).
If Jewel Seeds are the only items that can power artifacts without a mage actively channeling it, that's a problem. But if "robotaxi" means what I think it does (no driver), that doesn't seem to be the case. I was basically assuming that building robotaxis doesn't require spellcasting ability, and suggesting that you go into that kind of craft in the "bespoke custom" niche.
If Jewel Seeds are the only items that can power artifacts without a mage actively channeling it, that's a problem. But if "robotaxi" means what I think it does (no driver), that doesn't seem to be the case. I was basically assuming that building robotaxis doesn't require spellcasting ability, and suggesting that you go into that kind of craft in the "bespoke custom" niche.