I'm not sure what you're talking about here. Are you referring to LCD TVs? Plasma? OLED? What about a CRT that displays images at the speed of light with a true 0ms response time? Are we factoring any kind of image processing on the newer TVs, or is this an unprocessed image like an old TV or computer monitor?
If you're saying that it's a hardware limitation of the gaming console itself and not the TV or monitor, then which console are you talking about? 360? PS3? Do other Consoles show evidence of faster response time? We've already seen claims that PS3 has longer response time than 360. What about computers and not consoles?
I don't want to call out your tech-talk as BS, but as a big tech person myself (particularly where video output is involved), I don't want anyone to be misinformed of what's really going on with the input lag.
For a big tech person you sure sound clueless. Let me explain shortly, and I'll provide you some links at the end of this post in case you want to delve more deeply into it.
What I'm talking about is how games are rendered. It has little to do with the delay on your TV, although that just adds to it and makes the delay worse. Rendering games is not exactly the same as a simple video output. When you press a button, the signal needs to be read, then translated into what that button is supposed to do (game logic), and after that it needs to be translated into an image code that's sent to the GPU and then the image needs to be rendered by the GPU to be sent to your tv.
In theory, the fastest output is the 3rd frame. With a PC (and even the consoles), you could theoretically reach this provided the CPU is powerful enough or the game logic is really simple to be computed in only one frame (16.7ms). I wouldn't be surprised if the menus on both the X360 and PS3 had a 3 frame input lag, because up and down, left and right are very simply things to calculate. But as soon as your game logic is more advanced than say a color change on screen, you need more than one frame to calculate everything.
Basically, on the frame that you input something, nothing happens because that frame has already been rendered. You can call it the zeroth frame if you wish. During the 1st frame, basically every calculation up to and including the image code needs to happen if you want the fastest 3 frame output. During the 2nd frame the GPU will render it, and on the 3rd frame it will be shown on your screen, provided everything went smoothly. Now because game logic and the translation into image code is fairly complicated in practice, it takes at least two frames for games to calculate everything before it's sent to the GPU to be rendered, thus having an input delay of 4 frames in practice. And if it's not because of the game logic, it can be because of the V-sync method used and so on.. And this is all without the input lag of your TV.
So basically, input lag is caused by the complexity of the game logic. But, it can also be caused by bad programming. Unnecessary loops and so on give the CPU more work than needed and can increase the input lag for no reason.
And on another note, screen tearing is caused when the GPU can not render the full scene in under 16.7ms (in the case of a 60fps game) and only part of the full image is sent to the frame buffer.
Anyway.. If you want to know more.. Here you go:
Programming responsiveness, basically a more detailed explanation of what I just told you.
Measuring responsiveness in video games, how input lag is measured. This is the same method used in the video provided in the opening post.
Console Gaming: The Lag Factor, basically same as the measuring responsiveness article above, except it's a bit more friendly since it has videos and such.
Edit: As for the PS3 usually having more input lag, I assume it has to do with the split memory, in which in additional frame is needed to coordinate the two. The X360 doesn't have this problem since it's basically one big chunk.