Interesting thought. According to Bob those sorts of enchantments last longer relative to the skill in the design (lets assume Luccio is pretty top-notch there) but also the Materials used with valuable materials lasting longer (unclear if they are valuable because they last long or if they last long because of their perceived value). So lets also assume that the swords were made with the full weight of the Council's financial might behind them. So with everything going for them, they might functionally last a damn long time even with the normal degredation. If they can outlast the Warden they were built on, the question becomes mostly moot. If not, it could make sense for the user (rather than Luccio) be able to handle the upkeep given the ultra-personal nature of them. For example I dont expect Luccio to be able to use /any/ sword even though she made them all, since they are tailored to the wielder.
Separately, there's been speculation in the past about the long-term future of the existing swords. Per WOJ they can theoretically be given to knew users, so long as that new person is close enough in personality to the original for it to resonate properly (paraphrasing). So if someday another jerk-nozzle like Morgan comes along with the right Fanatic'O flavor he might be able to use Morgan's old sword. But I'd been imagining that happening generations down the line, with a store room of magic swords that occasionally get passed on to the rising stars of hte Wardens that are Lucky (or Fated) to fit them. But you bring up a good point, they might all have wound down and stopped functioning by then.
