Since I was a child, my Father was an antique car restorer, show car judge and estimator of their value.
He passed ten years ago and taught me all about his hobby/business but in reality the future worth of these vehicles depends on availability of gas or another alternate fuel to run them, Ive known for a few years now that throwing truckloads of money into a vintage or collector car isnt a good idea these days.
Someday the internal combustion engine may actually become hard to feed if we can get enough people to agree to newer technology thats not harming our planet just to travel to the store.
Someday the fact that you have a million dollar Ferrari in the garage just means you own a piece of metal that you cant find fuel for and may actually become very expensive to drive, of course a million dollar car owner may be able to afford driving it but then public acceptance of your polluter on the streets may not be achievable.
I have two vintage cars, a 1929 Model A truck and a 1947 Ford sedan both fully restored, Ive only put 150-200 miles on either in the last 15 years, its not worth converting them to electric or other tech as the Model A is essentially a piece of farm equipment and the sedan isnt really worth throwing that much money at.
I also have two Mustang convertibles, a 1994 GT and a 1998 Cobra, Im saving the money to convert the cobra to electric and ford even makes a kit to do so, Id rather do that than buy a new car.
Its hard to know what will happen in the future but my thought is that throwing tens of thousands of dollars at that special car you want to drive for the rest of your days isnt realistic anymore, although Im not an expert Ive been around the hobby long enough to see the writing on the wall.
And it says someday that expensive collector car may just sit in the garage collecting dust because you didnt sell it in time.
My thoughts are have fun with your muscle car/ vintage car/ family heirloom while you can as I will do but expecting them to hold their value for another two decades may not be reasonable.
I rather have a nice house, pay the grandkids college tuition and enjoy my life than miss the hint that the car in the garage is heading toward lawn art usage.