I certainly can't call myself an economist, so any claims I will make on this subject will not need to be taken directly as any gospel.
A man who is an economist is Avinash Dixit and in an introduction on the subject of information asymmetry, he writes the following: 'Words are cheap; the employer wants you to 'put your money where your mouth is', so to speak. You offer your educational achievement as a signal that you have the qualities the employer wants. The signal is costly: you have to spend time and effort and resist temptations in order to acquire the signal. But more than that: the cost of the signal - in terms of time, effort, and giving up campus parties - would be prohibitively high to someone who lacked the qualities you are signalling. It is this cost difference - you, with the right qualities, can afford the cost of the signal but someone without them cannot - that distinguishes you from a would-be mimic or pretender and makes credible your assertion of quality.
Signals can thus solve the asymmetric information problem, but at a cost.'
It can be summarised that a seller knows more about a product than a buyer and that it is a precarious job for that seller to convince the buyer of the accurate value of his product.
Despite all romanticism, this fact has had quite a large influence on the prevailing taste in art over the last sixty-odd years.
During the 60's and 70's the general taste in art was one of reduction. Works were getting simpler and simpler in appearance, prompting the consensus amongst theorists to form around the idea that art was becoming immaterial. However, as anybody who has ever installed a work by Richard Serra can assure you, nothing could be further from the truth.
The works may appear simple, yet their material aspects are nearly always large, heavy and expensive. Champions of the immaterial such as Donald Judd, Carl Andre and Joseph Kosuth fit perfectly within this category. Judd once presented his gallerist Leo Castelli with a $250000 production bill in 1973 ($1.4 million in today's money) and buying 100 copper plates will cost you about as much as a small car. Kosuth is mostly famous for his neon works and as custom work easily runs into the thousands of dollars it isn't cheap. Neither is fluorescent lighting if you apply it on the scale that Dan Flavin does. The same principle goes for Bruce Nauman, Christo, Claes Oldenburg and so on.
These artists often worked with readily available materials in ways that don't necessitate any formal art training. But this does not make those materials cheap. As scarcity and uniqueness had so long defined the idea of value in art, high availability had been confused with low costs.
This wrongful assumption had nevertheless carried on into the next decades and by the time the 80's and 90's had arrived, the trend had clearly shifted towards cheaper materials and a smaller scale.
The difficult to handle and expensive metal objects had been replaced with wood, often of the lowest quality. Found objects were used everywhere and and the choice of materials was now expanded into whatever could be found in corner stores. From this came many famous works, varying vastly in character. 'My bed' by Tracy Emin, 'Empty shoe box' from Gabriel Orozco, Martin Kippenbergers' 'Peter' series, Felix Gonzales-Torres perfect lovers and the entire oeuvre of Andy Goldsworthy.
Of course painting flourished as well. The quickly painted work of David Salle, Jorg Immendörf and most famously Jean-Michel Basquiat, captured the zeitgeist perfectly and due to it's swift production was actually able to meet the demand in the galleries.
There was however a big problem with the fully realised idea that the 'true artwork', and thus its perceived value, was immaterial and therefore could not be equated to the 'mere object'. The problem was that the high value of the idea was difficult to measure as it could not be traded directly and this value was now inescapably bound to a possibly worthless object. As there was no reliable way to distinguish the worthless objects with valuable ideas from the worthless objects with worthless ideas, faith in the system inevitably came to a stop and the market crashed, with prices plummeting indiscriminately.
Like all insurmountable tragedies, this collapse of the market passed relatively quickly and by the time the new millennium came around, the world was once again ready to accept a new generation of artists. People like Ai WeiWei, Dahn Vho, Michel François and Ryan Gander. If one takes a look at the list of materials used by these artists, one finds such things as Han-dynasty urns, parts of beams and pillars from dismantled temples of the Qing Dynasty, Rolexes and Patek Phillipe, gold lighters, gold foil, animatronic robots and of course the classic bronzes and marbles.
The need for reliable signals of value has shifted the taste once again to more expensive materials and the artists who are consistently and explicitly using high-quality luxury items in their work have come to the forefront. This is reflected strongly in the plethora of shiny metal objects produced by today's post-graduates, who often specify the materials of their picture frames as to emphasize their rarity.
The idea that the intellectual aspects of the work are the most valuable may still prevail, but at least it is now traded in materials that will hold their value when those ideas have long been forgotten.
Isa Genzken is an artist who beautifully encapsulates the entire concept in a single oeuvre. She gained fame during the 70's with complexly constructed sculptures that were difficult to preserve and transited in the 80's and 90's to crude indestructable concrete objects. These days, she makes work with airplane fuselages, designer clothing and sometimes actual money.
Though some praise these changes as the versatility and daring of a complex artist, they may just as easily be explained as the output of a brand that is merely keeping up with the changes of taste in the market.