What makes no sense and is a stupid concept is that a martial arm in original condition is useless, that adding a sporter stock, refinishing the metal, and putting a scope on it suddenly makes it so.
Are you telling me that you believe that fitting a Timney trigger, for example, to a 1893 Spanish Mauser action doesn't add to the utility of that rifle? Is it OK to add a tang-mounted peep sight to a pre-'98 Winnie/Browning? What if I put a repro stock on it so that the original one doesn't get all beat up in the field - does that pass your litmus test for acceptability? At what point am I crossing the line between making good use of an old arm into the realm of whatever it is that offends you? When I take a 29+" barrel on a 1891 M/N and cut it down to 20"? Well, heck - don't look now, but the Russians started doing that during arsenal refurbs of their old 1891/30's back in 1959 and didn't think too badly of themselves for having done so.
And, how does putting $400 into a $100 rifle that will shoot 2 MOA at best make good monitary sense when a used Savage at the gunshow will run $200?
First off, these are your numbers and nobody elses. In my example, I have less than $300 total in a rifle that will outshoot any $200 used Savage, which is far better made than any $200 Savage, AND WHICH IS PAPERLESS, unlike the Savage. How much more plainly should I write it so that you'll understand these concepts?
Ever priced a sporterized Enfield 1853 or Springfield? Compare that to an original. BIG price difference. BIG difference in demand.
I don't know anyone in this day and age who has or would sporterize a black-powder weapon (if only because I can get a new-production Knight inline for less money and with the same paperless qualities). Moreover, that's not what was being discussed. What was being discussed was the refurbishment and possible sporterization of a commonly-available pre-1898 rifle already chambered for smokeless ammunition.
The fact of the matter is that a sporterized rifle loses its value. FACT, there, FACT. Somebody might pay more for it, but usually not. A Remington 700 will out sell a sporter mauser every time.
While this is a tangential argument relative to the thread, I think that it's worthy of discussion. Your statement is actually not a FACT - it's your OPINION based upon your observations. And my observations are not much different from yours, but I've also seen the flip side of this.
I've most commonly seen the phenomenon you describe relative to hack jobs on common rifles (M/N, M48s, No1Mk3s, etc.). After all, nobody wants to buy a rifle that's been hacked on unless they can quantify the quality of the work. On the other side of this, some of the most breathtakingly beautify and coveted rifles I've seen have been professionally altered MilSurps. Most of the truly exotic dangerous-game rifles have been built on large-ring Mauser actions, and many established names in the business hung up a shingle first and foremost to 'sporterize' Obendorf Mausers.
While anyone looking to buy a $100 Mosin Nagant and sporterize it should expect to wind up with a rifle worth no more than what they paid for it, I do not believe that it's fair to categorically state that the rifle will be worth less than $100. And if the value of being paperless is greater in their mind than the cost of the sporterization - how can I (or anyone else) tell them that they're wasting their money?
My point here is that we should not paint everything out there with the same brush. Not everyone trying to work on a rifle is an idiot, not everyone is gonna take a hacksaw to any ol' MilSurp that crosses their path, and not every rifle is fit to be maintained in its present condition without work. And yes - in my opinion, anyone that attempts to paint everything that they see with the same brush is talking out of their rear end. If this doesn't describe you, then don't sweat the comment. If you take offense at this, then perhaps you should wonder why.