Comment by amatecha

Hmmm, HTML has had layout behaviour that works at all viewports since its inception -- it's just that web developers have often implemented markup that that is inflexible. Just as you could make static/inflexible layout in any of the tools you mentioned, so could you do so with HTML. The regular flow of content on a web page has always been basically equivalent to "word wrap" (I don't know the proper term if there is one). The only noteworthy feature specifically regarding viewport resizing for web pages is "media queries" which wasn't necessary for ensuring a flexible layout.

It was always technically possible to have a flexible layout, it just didn't become popular/"standard" until around when mobile started being a popular medium via which to view that content. The prevalence "best viewed at 1024x768 or higher" was just a symptom of inflexible design & implementation, not an actual technical limitation of HTML.

P.S. I will definitely agree that laying out content in HTML has always been awkward, tedious, and inconsistent across browsers, hahah :)