^I was always pissed at the initial "restoration" of the model for how they handled it. As someone trained in the heritage sector who worked with conserving artifacts, it just really was disappointing on a professional level, and sad on a fan level. I could never see the same "evidence" they referred to.
Regardless- as to the OP query. I USED to be on the modular construction side, and I would say sections of it have the ability to be modular like saucer, nacelles, pylons, secondary hull, et c. But solid extrusion printing technology today, coupled with transporter/ replication tech of the imagined future, really made me reconsider that would be a more practical approach.
Huge devices extruding metal and synthetic material based Hulls. Replicators making the smaller components, beamed into place, really make sense. None of this physical welding non-sense either.
I can almost see a big ring for a secondary hull, or giant slot like extruder for a saucer, very slowly extruding this big ole starship. And in the case of larger items, in the modular form for assembly.
Of course there may be instances where there was an issue that requires more mechanical and physical hands on corrections and guidance- hence the need for onsite workers overseeing the build.
Of course it is time consuming because energy and matter to make this isn't free. And that's why they don't pump these things out like mad.
It also helps explain the ability to create those giant star bases.