No, most people do not user their computer with 30" external screens. Perhaps developers at FAANGs do, but most people are mobile devices, follow by 13" or 15" laptop screens. Older people often use larger font sizes or browser zoom on top of that (or both).

It's funny trying to use an Office application on just a laptop's screen. You're left with a tiny slice of real estate because menus have gotten so bloated and don't adjust for the screen real estate you have. What's comfortable to work in on a 2x" monitor is not the same at <15".

I've seen this in webpages too. You load a page and think there's an error but the "login" button is surrounded by so much white space that it doesn't show up in the browser until you scroll down.