Superior specs of the base LE/SE trims

That level of customization adds variables to the production process. that leads to more mistakes that need to be fixed, or taking the time to reduce the chance of a mistake. Before that, there is the entire process of the dealer taking custom orders, and submitting them to manufacturer, who then shuffles to the correct factory. Afterwards, there are the checks of making sure the car goes to the correct place.

That all adds to the cost, and why everyone of the common car brands quickly shifted to packages once someone came up with the idea. Luxury brands took longer, but now it seems custom features is only available on models with 6 figure price tags or are $40k go carts.

If it happened back then, the cars would have cost less than $2000.

The Opt A and Opt B's for the cargo area are going to use the same attachment points in the car's frame. Cheaper and less problem prone to have all the necessary holes or studs in the sheet metal for all the options than have two different sheet metal parts.