I think for most web apps it doesn't make sense to allow the width to get so wide, except when the content being displayed is a columnar list and even then it's a pretty marginal benefit.

What I've done is limit the max-width to some amount of px/chars and allowed the remaining space be empty, with an exception for when displaying tables. Even with tables, the bigger width is only beneficial if either the contents of the columns are large enough, or there are very many columns to show. The solution in my mind is limiting the column widths to the longest content.