The idea is the "semantic web". Success would look like almost everyone here having to know a lot more about the "semantic web" to do their jobs, such that I wouldn't have to explain to anyone what it was because it would just be how things worked, because it would be that important, and they couldn't operate without it because they wouldn't be able to compete against other websites without the staggering benefits that super-careful, expert semantic design brings them. Rather than just learning the layout and adding a few extra accessibility tags as needed.

As it stands now, it's very practical to just slap some <div>s down and do some CSS and be done.