While I do appreciate monitors have become wider, since IDEs these days are very screen real-estate hungry, I do believe it's a shame it means limiting the vertical resolution. I can live with 1080 pixels, but more definitely wouldn't hurt!
Production costs is probably the main factor, but the form factor is probably also important in and by itself - 16:9 is the standard for HD content, and the manufacturers are probably afraid of going with something else, especially as we see TVs and computer monitors converge.