The point is that HTML is almost 30 years old, and based on SGML which is much older (even though ISO 8879 is officially "only" from 1986), where SGML is just a formalization of typesetting practices established in the 1960's and 1970's. Given the depth of usage of HTML in everyday life (laws, contracts in ecommerce, medical records, personal communication, education, etc., etc.), I think HTML deserves better than being tinkered with all the time for no good reasons other than job security and/or achieving Webkit dominance, or other nebulous reasons at this point. At the very least, a standard should serve the purpose of defining a wellformedness criterion for a deliverable that you outsource to some HTML author, and that doesn't change all the time.
These are the first sentences of Yuri Rubinski's foreword to The SGML Handbook outlining the purpose of markup languages (from 1990):
> The next five years will see a revolution in computing. Users will no longer have to work at every computer task as if they had no need to share data with all their other computer tasks, they will not need to act as if the computer is simply a replacement for paper, nor will they have to appease computers or software programs that seem to be at war with one another.
Held up to that goal, HTML has utterly failed. And there's just no justification for attempting to complicate HTML, leading only further away from that goal, and by intent never coming to an end for a task that isn't terribly complicated, and increasing the scope without any sense of mental discipline, and without considering the scarce resources available, thereby creating a browser monoculture.