It is the "Treadmill Effect"!
One manufacturer decides that they will "improve" their product and by keeping both the new and old product on the shelves gain a market advantage over their competitor(s). Their competitors see what has just happened and decide to rush their new product off the drawing board (before all those nifty improvements are all working) to draw level again. Pressure mounts and soon everyone is on the treadmill!


Anyone want to buy my new Super Hyper Duodecacored Pentium with the Polyphonic Whistle and Nano scale Ultra Bright Plasma Screen?