Dan writes well but it's blah, blah, blah, and based on a false premise. What, you say? Tell me how many agencies are selling $1 photos? That's his whole soap box for 99c and prices ending in 9 which is about 40 year old marketing. Anyone notice that Wallmart uses the 7 for close-out items? Why's that? Maybe because they leaked the 7 to entice buyers to believe it was a much lower price. When was the last time you had a photo sell for a dollar on iStock?
He's right about the perceived value and you can take common products, put them in a fancy package and tell people it's premium quality, when it comes from the same bin as the regular stuff. But that's buyers who don't care about investigating what they buy and will buy designer jeans, because of the label on them, when they can go to a farm supply store and get some durable, functional jeans, for less.
Is Dan proposing that buyers can't look at a photo and tell if it's good or bad? Unlike chocolates, which are a perishable food, photos are an item that can be held and used and re-used. It's not a box of chocolates, where "you'll never know what you are going to get".

The buyer decides ahead of time, what they are getting and for what purpose.
Meanwhile, we are the product of a price war between agencies, it's not like a store, people travel on the Information Highway, without leaving their desk. (or phone?) The crux of the whole microstock success and why we are paid a relatively low price, compared to five years ago, is information, distribution and supply! The price of information (or photos) has dropped. The photos that meet the needs are easy to find through many competing distribution channels. The supply of photos is no longer limited or exclusive, there are tens of thousands of photographers with digital cameras, around the world, willing to work for a pittance.
It's not like and airline where there's a whole staff and equipment, marketing and advertising, and all kinds of other complications. It's one person with a camera, who uploads to an agency, who handles everything. People work hours and days and weeks and months, for some small sales. Most don't make a payout for agencies every month. Even more never make a payout and realize that we are expendable labor and provide unlimited supplies, because the supply far exceeds the demands. I'm sure the agencies won't be releasing the figures for how many photographers never reach payout and quit, which means 100% profit for the Microstock site.
The perception of a good photo may have some price connections, but only if a buyer is blind and doesn't see that Microstock is the best deal going right now. Fierce price competition, excess supply, same images at most of the sites. It's a buyers market.
And to answer the original question, what if... it would create a firestorm of price fixing and anti-trust suits if the agencies colluded to set prices higher with some kind of industry agreement. All you would need is one agency to disagree and stay low, and the whole house of cards blows over.
As long as photographers are supplying 20 agencies who are involved in the price war, and flocking to every new agency that pops up like a weed, the prices will always be as low as they can go. The only way to stop the undervalued photos is stop supplying start-ups, stop feeding the dormant sites, stop competing with yourself and driving the prices down.
The root cause of the low price problem is the photographers who are willing to take pennies for their work. If everyone on this forum quit tomorrow and removed all their photos from every site, in a week, a new batch of photographers would fill all the sites with new images.
The prices are low because there's no bargaining power on the supply side, the photographers provide the labor and materials and get paid slave wages. The agencies sell for low prices, because they get them cheap and can make a profit turning over the stock at a high volume. The buyers are happy because they get good quality images, for a low price.