There are many many people who keep a single window maximized at all times and alt-tab between windows.
It's the most basic form of window management, and it works pretty well.
It's especially helpful if you want to be able to focus on one thing at a time only, and not have multiple different windows with disparate screen noise visible at once.
I often operate in that mode, using a tiling window manager to have a single maximized window on my primary monitor, and optionally a tile of auxiliary windows on my secondary monitor.
I agree. I will do side by side quite often when I'm programming or doing a specific multi-tasking work, but my "regular" browsing is fullscreen. I don't see why I would browse the web (single focused task) on the left or right half of my monitor, that just seems... silly?
I maximize the window height, but limit it in width precisely because so many websites aren't designed for wide screens. Windows makes this easy: just double click on the top or bottom edge of the window. It's also sticky, so I can easily drag it to the centre of the screen.
It's the most basic form of window management, and it works pretty well.
It's especially helpful if you want to be able to focus on one thing at a time only, and not have multiple different windows with disparate screen noise visible at once.
I often operate in that mode, using a tiling window manager to have a single maximized window on my primary monitor, and optionally a tile of auxiliary windows on my secondary monitor.