some have multiple-object models and multiple materials each with multiple textures on them.
what’s more, they’re all parented to one another.
when i took a look at the Outliner once to look at all the data i put in one file, i was surprised by this:
that’s the visualization of all my objects in one blend file.
take a look at some of your projects and see how their outlines turn out.
Here’s one I started assembling from assets today for the 3rd scene in elephants dream. There’s a lot more geometry to come for this one, and there are no textures yet either, but they will be rendered in passes/layers so everything you’ll see in the final shot may not actually end up in this .blend file. Ther’s no greebling or dupliverts - all of the objects are hand modelled (lots of separate curves), though many of the ‘chunks’ were linked-duplicated perhaps 3 or 4 times.