we actually don't know how many people were working on building it.
(or do we? i don't.
maybe they had an army of builders and each of them had the 7y for his/her one dungeon
@ marss: i don't think they're primarily following a "just good enough to pass" approach.
the locations are stuffed with detail (even those nobody ever really enters, or have you ever been, like, inside solitude sawmill?), little stories and gags everywhere, most of which you don't even notice before your 3rd or 4th playthrough (or during modding), they could go with MUCH less.
also, many locations are highly experimental. they're not just running down their kits, they're abusing their assets in all ways imaginable themselves - and most of it all is flawless, when you build off the grid, you'll have like rock back ends sticking out at every corner and spend amazing amounts of time fixing these things, you hardly ever see anything of this in skyrim.
@ crossi: most of all, you get quicker with every next piece you make.
and a few other assumptions:
.) they'll make more use of stuff like object palettes etc than we do.
.) they'll never have to worry about incomplete kits, because they'll have the complete ones , and when they need a piece, i figure they'll just ask the modeler to make it. or make it themselves.
.) they'll never have to spend weeks to figure out what the hell the logic in solitude kit's naming convention is, because they named it themselves...
.) i could imagine every builder specializes on a kit. with a kit you know well, you don't need to think much about what piece to use, nor do you plan stuff that can't be made etc. saves lots of time.
.) seen the warehouse cells? my theory is this goes much further, like, on a "nordic rooms", "dwarven hallways" ... level