Can you still build components bigger than 500 tons on the ground? The lore says ships bigger than that can't handle the aetheric currents, so how does a sub-500 tons shuttle handle taking a 2500 tons engine from my factories to the orbital yard?
Maybe the engine itself is assembled in orbit.
I agree...
If we look at modern techniques at building large structures it makes sense that you build things modular and assemble them at the final destination. You do this with most structures and large vehicles/vessels today. I don't see why they would not do that in the future as well.
Modular construction is very effective and also good for upgrading, replacement, maintenance and repair etc...
I also think it is quite likely you have some sort of space lift capacity where you use a combination of anti-gravity and typical space lift technologies to get most stuff into orbit.
There can also be a combination of anti-gravity devices and strong tractor beams on the orbital space stations to act as space lifts or some such.
But I still think you bring up large pieces such as engines and other components broken down into modules.