I believe the reason makers do not continue some features is they want to keep the value of the earlier model up. If the kn7000 had everything the 6500 had and more, then the 6500 would go down in value as soon as the 7000 was on the market. So they drop features so users with still want the 6500 for certain reasons. And that is also why newer models don't get many new features or that high of an upgrade. Remember also that they need to save some technology already made for the next model. It is all a strategic marketing game.
Tony