The devil's advocate response is "How essential could they be? We went decades without 'em."
I don't think it's the right answer, but it's an answer that works (GNOME continues to be the dominant Linux desktop environment in spite of lacking that feature).
Completely realizing you aren't actually making the "devil's advocate response," but I think the response to that is "We went for a millennia without electricity, too."
Just because we went without something, doesn't mean we should accept life without it at this point.
GNOME has enjoyed the status of being basically usable, if not particularly good, throughout its history.
I still remember KDE going through what felt like years of being unusably broken during its clumsy transition from 3 to 4. That's a lot of the desktop Linux experience, really - everything constantly in flux, never quite usable. I don't blame anyone for this, it's hard to get stuff done without someone paying a team to do it, but it's really unfortunate.
After flip flopping a bunch, I ditched both GNOME and KDE for Xfce and haven't felt like I've missed much. It might need some better defaults, but you only have to fix them once on a new install.
Nothing huge changes, and really, I'm not looking for much. A launcher. A way to switch windows. Volume and brightness buttons/applets are nice to have. A system tray.
I've heard somebody somewhere along the lines call it the "Debian of DEs" and I can't argue with that.