I agree with this. It actually seems like a recent change, especially in live chess.
This is what I see in live chess now:
The graph used to be larger and I believe that the "playable" screen used to be wider as well. In other words, the large swaths of gray didn't used to be there. So the chess board was the same size, but the chat and graph to select games were larger.
I'm using a native 1680x1050 resolution on my computer and with this, Chess.com appears like a light strip with two huge black empty spaces on the sides. This doesn't look very good and can sometimes be downright annoying. Since the site seems to have a smartphone-friendly layout available, how come there isn't a layout designed for widescreen?