By the time it caught on, HTML did allow for very graphical web pages, and that's not even considering how popular Flash Player was when the internet had its in

By the time it caught on, HTML did allow for very graphical web pages, and that's not even considering how popular Flash Player was when the internet had its initial growth spurt. Technically, very early versions of HTML, especially predating CSS, were closer to epub than modern HTML, but there were so few web pages it's not a meaningful argument against your supposition. I think what's more important is that a significant portion of web pages have no more complex layout than a newspaper or slideshow, so why not make them easy to parse? Not only would it make browsing in Lynx easier, but it would work well with screen readers, which are the only way some people can browse web pages.