a young couple doesn't need 2x the space as a single person though
Now, if you add my partner, we could add another 1,500 square feet to the living space, you know, because of "stuff," and then we'd need to double the garage size for her art studio and project space.
And that doesn't include the space we use for a berry garden, fruit trees, and vegetables.
Another way to look at it is, do you live for experiences or do you live for building things? Are you a consumer or are you a maker?
I come from a family of makers at least as far back as my grandparents and our tools and using them gave our lives meaning.
These differences in experience and perspective alter the balance of need versus want.