They know their market.
They're not thinking logically - super-complex machinery that requires specialist and highly trained technicians to fix would suggest a similar requirement to build them in the first place, not a sweat shop factory that pumps out milllions a month for peanuts actual production cost just like any other phone.
They're just trying to maintain the cult status and incentive to spend real cash on a 'not much more to update' mentality.
The only super-complex bit is designing the thing and its PCB assembly process in the first place.