So I'll preface this with saying I agree with your general point: newspapers are crucial to do important investigative journalism work.

That said, Reuters does do solid investigative journalism work. One example is the Taser scandal recently: https://gijn.org/2017/10/02/how-they-did-it-reuters-massive-... They also have opinion pieces, and long form pieces, although these aren't seen as much as their standard articles.