Of course. Developers are the ones who always say "just configure it to your liking." It's the normal folk who need sane defaults!

Slightly more seriously, maybe the sane default should be a sane window size for the browser. Not everything needs to be fullscreen. Or maybe the browser window could be wide but could present a narrower viewport in appropriate circumstances. There has to be something better than having every web site separately specify whatever it thinks is a reasonable reading width.

I guess but a) backwards compatibility probably comes in to play b) can you imagine the level of bikeshedding