I think you're conflating "bigger monitior", "higher resolution", and "high-dpi".
> But it is not uncommon to see a website on a huge hi-DPI monitor in such a way that a heading takes 1/4 of the screen height
> if you buy a bigger monitor, everything just gets bigger, including most of fonts, unnecesarily.
I don't think this is the case at all? The web and browsers handle DPI scaling incredibly well. I don't think I've ever ran into an issue with it. Remember that Apple has been shipping high-DPI monitors for the past 15 years, and I've never experienced these issues of a website of a website not handling this. More or less, the browser completely abstracts this away - you have to purposefully screw things up to render things at different sizes depending on DPI.
> But it is not uncommon to see a website on a huge hi-DPI monitor in such a way that a heading takes 1/4 of the screen height > if you buy a bigger monitor, everything just gets bigger, including most of fonts, unnecesarily.
I don't think this is the case at all? The web and browsers handle DPI scaling incredibly well. I don't think I've ever ran into an issue with it. Remember that Apple has been shipping high-DPI monitors for the past 15 years, and I've never experienced these issues of a website of a website not handling this. More or less, the browser completely abstracts this away - you have to purposefully screw things up to render things at different sizes depending on DPI.