A more fundamental question if I may ask --
Why is a rate desk necessary? Is it because the codeshares, upgrades, fare classes, etc. have become almost too complicated and cannot be avoided? Is this why we can never fix / refund / change an itinerary online by ourselves and need to get UA's agents involved?
Compare/contrast this with some other low cost carriers, who simply do not create such complex fare systems (or have codeshares I suppose), and probably don't have to have such extensive rate desks? Is this a mandatory part of being a large international airline?