[csande17]

What's impossible about it? I've seen devices in the past that can combine multiple HDMI signals into a single image (like picture-in-picture, or making one high-res display out of several lower-res video connections). And if you can do that, surely you can do instant switching just by toggling between "full screen input 1" and "full screen input 2" layouts.

[beebeepka]

Were any of these devices monitors? Were they cheap? Like it or not, price is a major factor.

On top of that, just look around - there is no perfect display,no matter how much one is willing to pay. Every single one has major drawbacks in certain areas.

[TylerE]

Also, if all your inputs are the same res(or even aspect ratio) and frame rate you avoid a gazillion edge cases