As for me, I like the “do one thing well” philosophy — I don't want my terminal to manage multiple sub-‘windows’, because I already have a window manager that I like just fine thank you.
`tmux` is actually more than I want, because it interposes itself as a terminal emulator in its own right (hence, per the thread parent, requiring its own sixel support on top of the display terminal's) and use `dtach` instead: it's just a pass-through session holder. Something like `tmux` is necessary when you want to connect to a session from significantly different terminals (say, iTerm on a Mac and Konsole on *nix) but I don't do that.
`tmux` is actually more than I want, because it interposes itself as a terminal emulator in its own right (hence, per the thread parent, requiring its own sixel support on top of the display terminal's) and use `dtach` instead: it's just a pass-through session holder. Something like `tmux` is necessary when you want to connect to a session from significantly different terminals (say, iTerm on a Mac and Konsole on *nix) but I don't do that.