It does kind of "sit between the program and the terminal," but it's not much useful in the context of this discussion. Going back to the starting point, the pr

It does kind of "sit between the program and the terminal," but it's not much useful in the context of this discussion. Going back to the starting point, the problem is that programs and terminal emulators have very limited means of communication. This is why a seemingly straightforward feature can't be implemented by the shell in a straightforward manner. screen is just another terminal emulator and nothing more. While screen is undoubtedly a useful program, it offers no additional means to solve the problem.