I’m feeling kind of the opposite lately. I’ve been considering going to a single monitor setup, because I feel distracted by everything that’s not on my primary monitor. I keep all of my “focus” items on the primary, and non-focus items (slack, discord, calendar, etc.) on the secondary monitor.
Maybe I should have elaborated further. I do a lot of tasks where I need to switch between 3 or 4 different windows/programs frequently. On a single screen laptop, this quickly becomes tedious, but on a multi monitor setup it’s much easier to keep everything organized.
The productivity aspect that he is talking about doesn't have to do with focus. Its significantly faster to work on anything with more screen real estate.
My primary monitor is 5k, so I have a lot of real estate. But even still I mostly organize things into virtual desktops with two windows each, e.g. browser + notes, vim/ide + documentation, obsidian + notes or references on whatever I’m writing about. If I don’t do that I get distracted way too easily, not even counting the stuff on the secondary monitor.