Because it doesn't appear to either be designed at a consistent scale or be a solid rectangular cuboid making volume feel like an even less accurate basis for my silly joke.
And I think for the actual value you get, scaling by volume would actually be more accurate.
I think scaling linearly works better here
That only determines a constant factor though, the scaling of build time for a given method should roughly follow volume.
Would you say that building a Lego version that’s twice as high takes double the time?