"in 1954 for ~$10k you could have stashed away a Mercedes 300SL "gullwing" or better yet, ...4 Corvettes."
True, but there is a lot not being said here. For one thing, 'stashing away' a car isn't that simple, if you simply bought the Mercedes or Corvettes and plopped them in a garage, time would eat away at them,unless you took special precautions. Rubber breaks down, paint fades, lots of things go wrong because of climate change, hot to cold, moist to dry, etc. To maintain it in the kind of condition that can generate top prices, you would need to store it in a climate controlled environment for 50 years, to make sure it was absolutely mint, make sure the rubber on things like weatherstrip and bushings don't dry out, tires disintegrate, paint fade, you name it..and how much would that cost?
More importantly, the cars you see going for big bucks at the auctions likely have been restored and are in literal concours condition, and that costs a lot, on one of the gearhead shows (I think it was chasing classic cars), they have this storage locker find Ferrari that could go at auction for several million, but required close to a million in restoring it costs....
And time alone doesn't mean anything necessarily, you could have preserved a lot of cars from the 1950's, cars people loved, and today you likely wouldn't sell it for all that much relatively, in real dollars might break even if you are lucky, and again you had to keep it for 50 years, 60 years.
In terms of collecting, while it may be true that keeping stuff in a sealed box will enhance its value with some collectors, the same way that an 'original' car can be worth more, not just matching numbers, but for example having things like the chain of ownership and proof, service records, and so forth, but in the end the 'bump' is relative, a car has to be desirable first for this to apply, and that bump is likely to be small (unless the car has a 'story', for example, that 1956 Mercedes was owned by (some deceased person who died young and spectacularly)).
If having stuff in a sealed box floats someone's boat, if the anticipation that maybe this will be the next big thing, makes someone happy, I say go for it, but I also will add that with most of the train stuff you likely will see sealed in the box, like a modern train set, it is very, very unlikely, even in the future some period years, decades out, that a new 'boom' will happen with this stuff, unless it is very rare for some reason. Even if you have the last sealed in box train set containing scale passenger cars and a hyper detailed Hudson, it is unlikely that will be like a rare instrument or something, the post war Lionel craze to a certain extent was driven by collectors who were of the generation who thought they were hot stuff, had the money to buy it, and created excitement (read greed) among those who never looked or played with trains, but saw it as the next bubble after beanie babies and the like *shrug*......cars are a bit different, though I wonder in 10,15,20 years what that world will look like, you look at the car auctions, you see a lot of guys who look a lot like the guys who have trains, and there is a decided disinterest in cars among younger people from what I can tell, so who is going to be the collector? There always will be some, a rare bugatti royale or a ferrari with a pedigree will always have cachet I suspect, but will we continue to see muscle cars from the 60's and 70's selling in 6 figures when our generation(s) are nearly gone, and the younger kids are now the 'old farts' grumbling about the young' uns? My own personal feeling is like the member of Pink Floyd who has a collection of performance cars and has a business renting them out for people to drive, he said these were not works of art, they were meant to be driven and enjoyed, and to him (and me) whether cars or trains, not much fun in just letting them sit there
...but that is me.
