I remember being multimonitor at some point in my ancient past. My parents had an old IBM with a physical switch that toggled from "PC" to "AT" speeds (2.86MHz to 4.33MHz), and if you flipped it while the machine was running, weird shit happened. Usually stuff crashed. That computer had a monochrome monitor I ran at 132x43 and a CGA I later upgraded to EGA just to play new games on it.
I don't remember when it was that I made the transition to "laptop as primary computing system," but at some point I abandoned the desktop. I don't even remember the circumstances. I just remember that, at some point, portability became the thing I cared about and needed most, and docking stations weren't that high on my priority list. So multimonitor was just never really an option because that second monitor had to be as portable as the rest of my rig.
Now, of course, that second monitor is definitely an option again. I know @mawr recommended one to me, but I've forgotten the model (( Hey, @mawr, can you shoot me a link to that portable second monitor? )) but I've gone so long with a single monitor and my habits adapted to it that I don't really feel like the second screen would benefit me all that much, and I suspect the ability to leave distractions on the other screens would impede my work progress.
All of which is really just sort of an anecdotal amusement to me. I'm typically the only person in any office setting who only has one monitor, or one monitor and a laptop, and folks wonder how I get anything done, and I wonder how they maintain focus with all the things they're looking at all the time. À chacune sa goûte.
Of course, i may just be crazy and there may be real benefit I'm denying myself. It wouldn't be the first time. I used to write fiction in vim, too.
@literorrery I use one monitor for my terminal windows while coding on the other most frequently. Also as a permanent place for my mail client to sit (on a separate virtual desktop).