My 2 cents:
The older these cars get the closer the price to mileage gap will be. Once a car ages to a point, with fixed quantity, then the difference between a "virgin" and a 20k mile (but perfect) car will close to a minimum, possibly 10% difference. Point being - virgin, cars will be less mechanically sound than lightly driven cars (lack of use destroys cars - rusty internals, rotted seals, etc.). Now if you plan to keep the car a virgin and put it in a showroom/museum then the value to that buyer will be more than a buyer who wants to collect the car and enjoy/drive it on occasion. Even in today's economy. Look at the prices of Hemi anythings in basket case form - look at the value/price of them in virgin form. Now look at the cost to get the basket case to virgin form because nobody buys a basket case to collect.
The virgin cars will always retain and produce more value at sale - but how much?. All the other cars as they age will grow in value that is closer and closer to the virgin car price/value as the supply diminishes. There is a point of diminishing returns. Basically a virgin GT is $225k - a 10k mile GT is $135k-145k. An $80k+ difference. Move that out 15+ years - the gap will close considerably to within 10-15% difference - NOT 65%+. If I had a virgin right now that I bought for ~$175k and could sell it for ~$225k right now I would. This will be the greatest difference between the virgin & used values (possibly for another 3-5 years). Unfortunately the GT is simply NOT RARE, yet. You can still shop by color, mileage & even mods. Once the GT becomes a car that if you want one you take the color available and just be happy to have one and have one that most likely will require some level of restoration - this is when the gap closes between the Virgin car and the others and the fact that it really doesn't matter anymore. 30 yr old virgin GT - more value? maybe, just don't start it or your blow the engine and it will start leaking out every seal - then you'll have to "restore" the virgin with parts from the guy who bought all the wrecked ones because there are no OEM/NOS parts remaining. If that makes any since...
Depending on your frame of reference and your ability to store cars - the best investment might be to buy up all the totaled & wrecked GTs and wait 10-15 years. Then you will be at least doubling your money without having to do anything. It's like a Generation 1 Viper right now - they are appreciating slightly as a complete car but the parts value is worth more than the whole car. The Gen 1 Viper is at the mid-point of the cycle. In another 10 years they will be "rare" and worth more than the Gen3 Vipers. Because at the 20-30 year mark buyers cease to base their purchase on vehicle performance and base it on different values (rarity, history, condition, emotions, etc.). These are the true price drivers - let's face it. The Heritage GTs are worth more because of paint - history.
But what do I know - I'm just playing the game (collecting). Win or lose financially - you can't drive/enjoy your portfolio.... Sorry for the novel.