What do you mean? It perfectly adapts to any browser width; if you want to resize it, just resize the browser window. It's perfectly readable on both a 4k screen and a small phone.
What more do you want? :D
What more do you want? :D
No thanks, I'll take fullwidth content anytime over that....
Otherwise, the other option is to scale up thr text size, but that takes up precious vertical space on wide screens, and doesn't increase information density.
Obviously, text columns may only make sense it certain scenarios - a minimum amount of text might be required to justify a second column as opposed to just limiting the width of the first column.