They existed for a while; but were odd and expensive and by the time cheap commodity PCs could push enough pixels to make one worth using they were also often pulling double duty as DVD players, with 4:3 and 16:9 ratio content.

Mid-range and higher monitors often have stands that allow for 90 degree rotation of the screen, so the wide screens could shift to vertical; sadly a good way to openly communicate that back to the GPU and OS hasn't been a priority.