Surely the solution to the furnishings and buildings to some degree would be to copy the real world: outsource. Not insource, properly outsource:
Create an industry environment such that virtual furnishing specialists can exist.
This might sound utterly batshit insane in isolation. In a world suffering from yada yada yada we have resources to spare on virtual professions etc etc etc. All that crap. But think about it: What we have at present is a bunch of companies each re-inventing the same blasted wheel. I'm not suggesting that a stage set in the office of the CEO of a design company not utilise unique furniture -- of course not, the NPC itself is a designer -- but rather that there's no reason the slums in Game A by Developer AA set in the year 20XX shouldn't have the same furnishings as the slums in Game B by Developer BB set in the same year 20XX. Suburbia too to an extent. Consider houses built from generic plans in outer suburbs.
In reality we have IKEA. Bunch of vikings, cheap hotdogs, frozen meatballs, shitty stub-pencils, allen keys, bookcases named after tall, fair and mysterious men. That's most of the Western world. But even beyond that, life isn't dissimilar. Presently I live in a small nation not in the Western world where every apartment comes with the exact same crappy chair. I'm sitting on it now, the rim of it jabs up into my butt and makes me lose bloodflow after 5 minutes. I seem them in businesses too. Same cheap chair. Another example: I grew up on the exact same model of bed you'd see in cheap motels across an entire country. That's a different country by the way, and I believe they weren't even IKEA models either, just another mass-producer existing in competition. What I'm saying is this shit isn't a country or locale-specific thing, that's just how business and economies of scale work in this era. Believe it or not, 1990s game design principles actually mirror reality for much of the world.
To an extent, the same approach can work for apartments too. To repeat things without it feeling weird, developers just need to observe reality and take stock of areas where uniqueness can and should be sacrificed.
Sure, for games with unique design aesthetics (fantasty stuff basically) this approach wouldn't work, but these games also have the design-space to simplify ones surroundings. It's only realistic shooters and the like that need a realistic room, so why not take a realistic approach?