Many reason's go into each owners build and reason for selling--
Economics is probably the largest--if it wasn't we'd all be driving around in SAIs, Kirkhams, or ERAs with 427 SOs
Give you an off auto example-- 10 yrs ago We bought a off-shore cruising sailboat for 82k--put an additional 15k in it the first year we owned--sailed it for about 5 yrs--pulled it out and began a refit--put in an additional 10k over the next 3yrs in upgrades--that's an investment of 107k--sold it for 85k early this year--soft market--I still felt we did well because we enjoyed he boat --
If we sold our 2yr old SPF today We'd probably be able to get maybe in the mid 40k range and it doesn't have a 427 but to us it is an investment in the "FUN FACTOR" of life