i agree, but not all have that luxury. a 3 monitor setup works for me. also for reason of course, the Panorama P1 in front of the mixer view, next to the Rack view, so great for mixing and making presets. and other stuff of course.
@antic604 is right, some DAW's work perfectly on one screen, like ableton and bitwig. but i use also multiple screens for them, even for reaper.. but i used to have only Cubase, a 3 monitor setup, was the best way, monitors are almost all replaced, with new ones, except one, but that was already quite new.
2 x 1920x1080 (24" and 22" touchscreen, the rack is visible on the last one, touchscreen works for reason, but not that well as for ableton or bitwig), 1 x 2560x1440 (27").
EDIT: that is why i am still considering to buy Reason 12, although, because of the behavior of Reason Studios, lately. the website isn't a reason+ clickbait anymore, the only progress.
doesn't mean me still like Reason 11 Suite, and the great third party RE's i have.