If the CUSTOMER (note the shout - they're the ones who ultimately pay the wages for the management as well as the deserving front end staff!) have a problem, they need a person. That person needs to know the particular airline system fairly intimately if they are to help effectively. Especially for the non-frequent or even the 'never flown before' flyers. So it need particular airline or agent personnel with good training. That's a problem, because it means spending money, which hits management bonuses.......
Then there's the machines (eg Venice Marco Polo - an airport nearly as bad as LHR!) that won't accept an airline FF card, but need to know the eticket number - which you don't know unless you've been to some difficulty to get it.