Don't confuse constraining an entire website's width for constraining the text reading width. You can gracefully have maximum reading width text columns with other content to the left and right of it to maximize real estate.
Also, don't ask users to resize their browsers to accomodate for a site's poor UX. That's called "blaming the user."
As a user, I expect to use my browser window to resize the content in my browser. Please don’t second-guess my preference.
9X% of web sites don’t do anything sophisticated, with columns or otherwise. They hard limit the content width regardless of the user’s window size, resulting in a tiny sliver of text.
Also, don't ask users to resize their browsers to accomodate for a site's poor UX. That's called "blaming the user."