It's interesting in that it sort of scales the opposite way. A $500k GIII will cost you about the same $3-4 million in annual operating costs as a $30-40 million G500, actually probably a bit more. Yet, a $250k 365GT will cost you about the same to operate (maybe a little less depending on how you manage insurance) as a $30-50 million 250GTO...
Clever attempt to justify those Ferrari maintenance costs Don? "But honey, look how cheap that was compared to a Gulfstream..."
Or buying a GTO or other very expensive vintage car. "Honey, it really won't cost us any more to own than our old 365..." If only!
How do these jets with 9+ hours non-stop flight time stay crewed? The G500 can go over 9 hours non-stop and the Bombardier 7500 about 16 hours. Do they need multiple crews? The G650 and Bombardier 7500 have small crew rest areas, but wouldn't you still need multiple pilots for those long flights?
9 or 10 hours is not a big issue with 2 pilots. It's good practice to add a third pilot if you are going to fly 12 hours (and required if it's a charter). Most of those airplanes do have crew rest areas, and otherwise you make do.