A frequent argument that this next generation of consoles will not, in fact, be the last is that there will always be a market for consoles. That is, there will always be gamers willing to pay for consoles and console games, that this market will never go away, and, thus, consoles will keep coming out. Let’s assume for a minute that this is true. The fact that there are people who are willing to pay for a next generation Xbox or PlayStation does not guarantee that a new console will be developed. It doesn’t matter that a market exists. There is probably still a market for Betamax. It doesn’t meant Sony’s going to start building and distributing the things again.
A console essentially boils down to a movement, and movements equate to change. One of the hardest things to achieve in life is systemic change, and most attempts fail. A change initiative is typically represented as an s-curve like the one above. It’s hard to change social norms. It’s hard for fashion novelties to become trends. It’s hard for viruses to become epidemics. It’s a question of inertia and at the start of a movement it always works against you.