I concur with your statement about getting younger people in the car clubs and at events. The very people that complain about their hobby dying off seem to be the older "purists" who refuse to adjust. I see the same behavior in a metalworking machinists forums in which I participate. If we older gray beards want to keep it going, it is our responsibility to to encourage them, coach them, mentor them, and help them, rather than ridicule their opinions. I work with many fresh out engineers who are outstanding engineers, and do not at all fit the millenial stereotype.
It's up to us, not them.
Not disagreeing with you, but the interstate highway system was built for 1950s cars.
Where people run into reliability issues is not driving the vehicle enough and allowing items to age out (whether it has miles on it or not things degrade with time).
What is different is our expectations, not many want to drive across multiple states with no A/C and so on. Meanwhile, the vehicles could do it if we let them.
*The above does not apply to stock model T and other pre-interstate era vehicles as they weren't really meant to go interstate speeds, but they can still runabout town.
@Gary_Bechtold - it doesn't have to cost $50K to be a muscle car. Now, depending on your point-of-view, definition of 'muscle car', and standards, there may not be a car out there for less than that that would make you happy. But you could certainly spend one heckuva lot less than that number and get a pretty presentable M-C.
Previous eras of high interest have come and gone. I've never seen a great roadside deal on a "full classic". I have almost never seen anything pre 50s be driven aside from to a car show either.
Stock muscle cars will become more and more of the hidden investment/brag piece and less a thing you see out in the wild.
What will be interesting (and probably sad) is if we get to the point that it is "worth it" to restore a current six-figure restomod back to rental fleet spec six cylinder green interior gold paint... --I think it is more likely that the restomods will drive on and it goes like the 32 Fords where there are more reproduction bodies out driving than originals.
I don't know...
The "Full Classic" collectors sort of started the hobby from the preservation/investment standpoint. And (as you say) most of those cars are relegated to collections to be looked at and driven very little. To me, those match up to the rare-spec muscle cars 30+ years removed (or like the Buick Skylark, Cameo pickup, Chrysler letter cars of the 50s if we need to fill in the in-between decades a bit). Same place that early exotics live in.
But the muscle car era also has the Model T plentiful examples situation going on as well as the Duece coupe/roadster thing where reproductions (and clones) are becoming common.
So while we will see less and less "real" GTO Judges just cruising around, there may in fact be more GTO Judges cruising around than were ever made as I can see this passing the fibreglass roadster market as the cars are a better fit for more people and their uses.
I think this holds for Mustangs, Camaros, Chevelles... maybe we don't see repop bodies for Oldsmobiles muscle cars or AMC.
The bigger risk for us not seeing these old cars is you local/state/federal government restricting or banning their use.