I mean, I have no knowledge of how car manufacturing works, but surely they can make the order and delivery process much more reliable.
Car manufacturing works like most production line manufacturing... they plan production of a batch (or item in the case of a car) based on the availability of the parts needed. That might be on hand parts (ie sitting on a shelf at the factory) or it might be when expected deliveries will arrive ("just in time" manufacturing whereby planned need for a part is ordered for delivery by a supplier - and in cars nearly every part is made by a third party not the car maker who simply assembles sub components!)
So manufacturing slots are available and into these slots the production planner has to place customer orders based SOLELY on the ability for all of the parts to be available on that particular day/week.
And that is why your order will bounce around for some time until its production status is "planned" - which is normally for VW locked in 2 weeks before the actual production takes place.
Hopefully you can see that for your order there are hundreds of seperate items probably coming from hundreds of different suppliers that all have to arrive at a precise time for your order to be fulfilled.... and this happens for 2.3 MILLION customer orders in 2023....
Just because your order needs the same part as 200 other golfs needing to be built, your order might not be assigned the parts that 199 others have, so you get knocked back a build week...
Is this complex? Yes absolutely.
Is this effecient? Well yes it is to a large degree, its certainly more financially effecient than say having a vast warehouse full of parts and doing stock orders when minimum inventory levels are reached.
Where it can of course come unstuck is when suppliers to VW have a hiccup (a Russian missile through their roof or a cargo ship stuck sideways in the Suez Canal) and amplified by hundreds of times due to the diverse sourcing of car components.
Does that help answer your question?