I'm sure this will be a stupid question to many but I know very little when it comes to manufacturing. Why is it so important to keep the line open by slowing production? Why couldn't you keep it open for say 6 months with no orders if you hope to gain some more in the short term?
It would be very expensive to have a production line open with nothing to build. Lots of parts have to be ordered up to a year in advance in order to make the finished product on time, and the supply chain for these parts has to have some guarantee themselves that it is worthwhile to keep a production line open. Not to mention that some parts are customer-specific. If you don't know who the customer is going to be for your next build a year from now, how do you know which specific parts to order? You're not going to spend several million dollars in parts inventory "just in case" someone happens to buy that specific configuration. If you let your supply chain shut down, will they be ready to start back up again when you are?
If you have nothing to build, what do you do with your employees? Pay them to sit around? That obviously gets expensive. If you lay them off, there's no guarantee they'll be interested in coming back when a new order comes in, so now you have to go out and hire, and train, new staff. That gets expensive, too.
There is also the question of having to maintain and keep up production facilities, machines, etc., or go through the process of mothballing them, and then bringing them back into working order. Shutdown and startup costs are immense. All of these issues also apply to your supply chain, as well (the companies that build the different parts of the wings, engines, tail, etc., all have their own issues of production facilities, staffing, etc.).
If you pay for the cost of shutting down and starting up again, it very easily exceeds the cost of keeping things going even at a reduced rate. If you can't sell your product even at the reduced rate, that means you can't sell it at all and you might as well shut it down.
That's why a "small" order of 14 planes, keeping the production line going for another 2 years, is so important to the 747.
The plural of Airbus is Airbuses. Airbii is not a word.
There is no 787-800, nor 787-900 or 747-800. It's 787-8, 787-9, and 747-8.
A321neoLR is also unnecessary. It's simply A321LR.
Airplanes don't have isles, they have aisles.