https://www.youtube.com/watch?v=gdnO1QZJ--M
:D
In my experience, the initial research/designing phase takes quite some hours (typically a good weekend), scaling up is must faster. In addition, most players who are into this typically have a number of creative worlds serve as libraries of past builds, so you'd almost never start from scratch.
On topic: This hard drive is incredibly impressive, and it's fascinating to see how the density changes between a 1K HDD and a 4k HDD.
Assuming that it's a single person? The use of "our" in the description (as well as the fact that they've got an online map in the last picture!) suggests that this is on a shared server.