Earlier quoted context omitted.
what hard is making a fully featured website, with panels no wider than 60ch. typically 60ch equal to 480px (font size 16px), so you need sidebars to the left and the right. which is fine, the holy grail was like that. but if you want to design a layout that look good in all screen resolutions, then a fixed layout does not work. you would have a dozen compromises and layout switches to make it work. at that point, fo…
main should contain the semantic content of the website, you can still make full width headers and footers and have on the side. Well and can be just where the name implies, depending on the screen width. This is really not that hard nowadays. How to do responsive design is no black magic and can be done with only HTML and CSS. You basically just need to wrap (no pun intended) your head around a few basics. Especiall…
Actually have you really design practical webapps before? Because your post only have empty pretty words with no substance.
Semantic html tags are just semantic, it is irrelevant for the discussion.
Responsive design is hard, have you ever try to reize your windows and see how your pretty website behaves? Leave aside stupid people thinking you only need to care about phone device (in portrait mode even) and laptop, most people also think 3 or 4 device widths is enough. Sure some smart one already promoted to break the screen by content, not fixed device size, but even that comes with some downsides.
To make a website works decent on all the possible screen sizes is a lot of work, I spent like 4 months updating and fixing my webapp when I first developed it.