If photography were a country, it would have experienced a transformation in name (and essence) from Mediocristan to Exremistan. In Mediocristan, most photographers were making a decent amount of money, not too high, nor too low, but around a median. In Extremistan, however, only a handful of photographers would make a huge amount of money, while the rest would be fighting for survival.
Well at least we're not the music industry. You want to see something scary, watch to the documentary "UnSound" when it comes out.
Insofar as your comment about the second hand market, the person who I saw recommend to hold onto even more limited addition "Artist's Print" that you could sell later, which is normal.
The real thing here is that exposure causes values to increase, so long as you can sell and keep the product limited. The question becomes, do you (or can you) handle this by yourself or do you need to have someone else to do it.
In most cases, artist need someone else to do it, due to lack of business sense, which is why most sell their work in others' galleries. If you go this route, having "Artist's Prints" and selling them later makes sense.
However, if you are like Peter Lik, and can handle all of the business yourself (and are good at it), then secondary market prices do not matter. You gain everything from the primary.
This is not a route most can achieve though. It takes a special kind of person to run just one location and make it profitable. Several locations becomes even more difficult and unachievable.
