I disagree and I think that treating the frontend and backend as different concerns is one cause for the big balls of mud we end up with. For example, many treat the backend as if it doesn't require design or taste for good user experience and many treat the frontend as if it doesn't require solid engineering. They are wrong of course.
Backend and frontend concerns are completely different, and it's fiction that you can simply wave those concerns aside and write the same sort of software anywhere in your stack.