The philosophical argument is called Theseus’ Ship. Here is a better comparison for you: Unreal Engine. It’s “the same thing” since 1998 or so. There’s also idTech engines, which are “the same” since Quake. Either engine would better fit the Cologne analogy.

Your city comparison also misses the point because Creation 2.0 is still using the equivalent of roman aqueducts and plumbing in 2024. They might work, sure, but not for a city of 1 million people where every building and home has its own plumbing. A better comparison would be a city that has some road holes older than some of its own residents.