Well, hardly "early 90s web stuff". There was hardly a Web then, let alone XML and CSS!
As far as standards go - like any other standard relating to digital information, the EPUB standard gradually changes and improves as the technology changes and improves.
Originally Posted by wannabee
While ePub is a standard and little guys play by the standard rules you have to think that these behemoths didn't get where they are by playing by the rules.
I'm just going to highlight a bit of web history, which is relevant here, I think:
History of the Web Standards Project