As someone who works in an engineering field, my short answer to the question "Are game developers architects?" is no.
I think what's closer to the truth is that video game designers are good at drawing influence from real life. Most buildings and structures you see games are based on and/or inspired by something real that likely hasn't fallen over or broken itself. So the fact that buildings, structures and machines in games generally appear sound in concept from a real-life engineering perspective is less to do with a game designers understanding of engineering, more thier ability to mimic it.