Well there is that, but consider the fact that no matter what you build if there is not someone who enjoys your passion for shooting and hunting then your masterpiece will most likely be sold for pennies on the dollar at some auction site. Heirs who are not into your hobbies will much rather sell your toys than hold onto them. I just sent 10 of my firearms to auction since my son or any other people I know will not cherish them. Better I sell them at auction then they, at a local auction where a $1500 shotgun will go for $200. Many of my students that are really into shooting and hunting will be the recipients of whatever is left after I go to the rifle range in the sky. Bless them all.There's a fair point here to be considered.
If/when for whatever reason you or your heirs choose to sell your custom rifle you're probably going to take at least a 30-50% beating when you do.
It's not at all uncommon for guys to end up taking less for the rifle when they sell it than they spent on the parts.
On the flip side, a custom coming from a good shop is going to come with guarantees you'll never get from one of the bigger manufacturers.
I'm not at all concerned about resale value myself because I have no desire to ever resell any of my custom rifles and if my heirs decide to they deserve a good beating.