Your assumption is correct. Some owners do not "daily drive" their NSX, they have other vehicle(s) that they use on a daily basis.
I'm a good case for this - during my entire ownership of my NSX, I have always had 2 other vehicles (and an occasional motorcycle) to drive. So all of my vehicles have low mileage for their age. While the NSX is my favorite, I also have found pleasure in driving the S2000's, MR2, C4 Corvette, 914, the Highlander for fam trips, and now the Boxster. So my 01 NSX only has 13k miles on it - I'm not trying to "save it", but simply enjoy it when I drive it - not worried about what it might be worth now or anytime in the future.