I do browse with JS off by default (usually FF with noscript, though occasionally with simpler web browsers), often leaving pages if they require JS while they shouldn't and I can avoid those, and I know others who do the same.

Maybe a poll would be more suitable for this kind of a question though, and I guess there must be some already collected statistics around.

Edit: Speaking of "LiteMode" and accessibility in general, I think it's also nice to not go too heavy on CSS or assumptions about fonts. I used to override CSS (browsed quite a lot in the dark, so enforced a light-on-dark theme), to use textual browsers, and still disabling web fonts and setting a minimal font size, which occasionally leads to slightly messed up markup and related issues. Though those sorts of things tend to be covered in various accessibility guidelines.