There are several million M/Ns out there that are in such poor shape and have bores like sewer pipes that I doubt we'll run out of actions to customize anytime soon.

The Mosin Nagant is the most manufactured bolt action in the history of firearms. I have read numbers from 87,000,000 to 108,000,000. That's more then all the Mausers ever made.

Remington has made about 4 millon M-700 so far. So the M-700 is WAY more scarce then a Mosin Nagant. Yet no one thinks a smith is an idiot for customizing a Reminton 700. So if Remington can make a mear 83,000,000 more M700s they will then equal the "scarce" Mosin Nagants
You know............in 500 years they will be rare too.....Oh MY!!!!!!!!!!!!!!!!!!!

To take a $50-$60 M/N and turn it into a very nice sporter worth several hundred dollars and in some cases over $1000 is a good thing to do, not a bad thing to do.

I'd agree it's best to leave 100% original Military rifles that are in 85% or better condition alone, but those that are in about 15% condition are close to worthless and I doubt they are going to gain much value. Those that worship things might be better off to warship VW Bugs or an 8 track recorders.