I seem to have arrived rather late to the discussion on collecting trends, dropping prices and the youth of today but here goes...
If you look at the general field of 'antiques' then there's little doubt that the movement of prices is cyclical. To give a specific example, in recent years the prices of musical boxes, davenports and many other pieces of furniture have dropped considerably. The very finest pieces survived the fall rather better than most but whether the nice but more ordinary examples might recover the value of their old glory days - who knows? Curiously it was the downturn in the Japanese economy that dented musical box prices. Prior to that happening a few years back, dealers from Japan would come to Europe and systematically clear specialist shops of stock...and then they suddenly they stopped coming and the prices collapsed. Victorian oil paintings however went from being despised in the 60s and 70s to gold dust status, with the best examples jumping from hundreds or thousands to hundreds of thousands...nay, millions!
I think that being the finest and rarest does help future proof to a degree, unless of course value has been wildly inflated by a fashion rush alone. I keep expecting the modern art market to collapse but the emperor's new clothes syndrome doesn't seem to have crumbled yet. And of course with the millions flowing into modern art, certain pieces/artists have arguably moved away from being objets d'art into being investments and currency. And if people with power and influence own pieces they have the power and influence to ensure others agree with the value they place on these items too. They keep it expensive and aspirational for certain types of collector with the result that ownership gives you a certain 'status'. But twas ever thus!
On the poster owning front I can only assume that there are gold standard pieces that are also unlikely to wane? Like original posters of iconic films like Metropolis or King Kong I assume? (I don't collect movie posters remember!) Elsewhere in the poster collecting field things might be slightly different. Popular culture obviously plays a role but certain poster artists have earned the respect of the art world in general and have transcended popular culture to become 'art' thus helping to future proof them. I'm thinking of icons like Toulouse Lautrec and Alphones Mucha here.
Thinking of the younger generation, I have two sons aged 21 and 23. I've tried to introduce them to a broad spectrum of the arts and of course that includes classic films. But you wouldn't believe the amount of persuasion in takes to get over that initial hurdle of 'It's in black and white!'. In spite of this, 'Citizen Kane' and "The Third man' went down very well indeed. Now when I was growing up there were two or three channels that everybody watched in the UK. Television was a shared experience that brought you into contact with things that you might not have been aware of or sought out. This included loads of old films - films which I grew to admire and have affection for. This experience developed interest and must have made collectors. What was there to own connected with a film back then? DVDs. toys, t-shirts? Well I assume not. The only thing you might seek out was probably the poster and publicity items; an experience which doubtless started the collecting bug for many here today.
Nowadays children can choose from a variety of different audio visual sources and - if they wish to - simply consume more of the same single-minded thing they already love. They won't easily stumble across old black and white films, or indeed anything that isn't more readily here and now. To my mind they are less inclined to look back and more likely to look forward to new things/movies appearing on the horizon. My eldest loves manga and anime and he spends hundreds on Japanese figures and collectibles. All items that have been designed to sell and re-promote the films/comics they come from but thanks to my evil involvement he'll also watch movies from the 30s, 40s, 50s as well as Laurel and Hardy, the Marx Brothers and the great classics - and he likes those too. The battle is not yet lost - at least not in this household!
