So my group has been playing for about a year now; maybe more, maybe less; and are all around level four.
Which is absolutely fine: we've all enjoyed the progress and no one seems to mind being "low" leveled, though granted most of my players hadn't played before this campaign.
The real point is that DnD is a long-run game, at least when you play it right. And by right I mean good ol' OSR style. Because what's the point if you never get to see any improvement? But my opinions on that are old news and I digress;
So I have laid out almost all of the continent of Hommund, which should encompass levels 1-20 or so. Which means that, at the current rate, it would take my party five years to explore all of Hommund. I have also drawn up four other provinces, for the most part yet to be populated with dungeons but still existing either incomplete or as concepts and maps.
This point brings me to the real gist of this post: Worldbuilding will never be an art.
At least not in the traditional sense.
See, obviously it takes a great deal of creativity and imagination and some talent to build an entire world. It takes creating ideas, having the patience to flesh out each idea, a knowledge of the rules you are writing for and the ability to create elegant systems that all match your aesthetic, and a persistent conceptual vision.
But the problem is: no one will ever appreciate this the way they appreciate a painting, or a movie, or as closely as possible a long novel.
Because an entire world cannot be easily consumed. No one ever reads the whole Silmarillion.
Traditional art has always been something that one can easily consume within a reasonable unit of time with relative passivity. The problem with DnD is: to most people, five years (at very least) is not a reasonable amount of time.
And then comes the matter of passivity. No matter how much you get into a book, you are still reading it. You can only look at a painting while it hangs there, unresponsive, within its frame.
Playing a long-form DnD campaign is like experiencing a play from within it, except there is no other way to experience it. Whole masses like to watch plays, and obviously some groups like to act in them, but if no one could ever witness a play without acting within it, even on improv without any timecost besides, the crowd might last a few weeks and quickly dwindle. After months even actors would tire.
And on top of all that still another cost: the burden of contribution.
In my game, a burnt village exists only because that's where a player said he came from. A cult and subsequent evil lair exists because one of my players said he was hunted by Vessa-worshippers, which in turn led to a bit of Hobbit history and an entire dungeon's plot hook and final "boss".
You read a book, you do not edit it with your own contributions (normally). Thus, you remain passive to your entertainment. Even in a video game where you can make choices, you still lack true freedom as all of your choices had to be pre-programmed by someone who had the same idea.
Worldbuilding is unquestionably an artistic effort and a remarkable feat, but it will never be an art in the traditional sense. Only a handful, if any, people will ever say "I liked Greyhawk better than Hommund, but I think the werewolf castle north of Termine Bay had a better atmosphere than the keep by the southwest shore." Because that is ridiculous and no large enough group will ever have experienced both worlds in their entirety for that conversation to last more than two minutes. One and a half minutes for guy A to say all that, and the next for guy B to slap him upside the head for thinking that could last as discussion.
This also just shows us an unintended secondary point: art is something that has to be shared by a community that agrees upon its importance and artistic nature.
DnD, being a game played by groups of maybe a half dozen at a time, inside together between friends close enough to share a sort of dream, is relatively insular, and while a large community may exist on the internet, it is dwarfed by the public population that has no idea we exist. And even within the online community, half of people are playing the wrong games (*cough WotC cough*) and half of what remains doesn't take the serious look to realize that what we build together could be art.
I'm all for just enjoying your games and leaving it at that, but so much of human effort and what gives us joy is artistic simply by that nature that it would be a shame for none of us to ever stop and give it a thought.