Although I don't live in Denver, I have a lot of family there and visit a lot, so I'm always checking web sites to see what's on while I'm there. The Denver Art Museum seems to be doing well. They have an intriguing new building by Daniel Libeskind in downtown Denver that's worth a visit and seems to attract a lot of tourists. And the region does seem to have a lot of "arts fairs" appealing to tourists, wonderful appreciation of historic preservation, and many lovely little galleries and museums.
But the Performing Arts Center in downtown seems mainly to show a lot of touring Broadway shows and plays. The only dance there since I've been paying attention is the Colorado Ballet and they'll only have three programs there this year. The historic (and recently restored) Opera House is beautiful and a wonderful venue, but it's huge, so smaller groups couldn't make that work. The Vail Dance Festival that we visited last year (and will again this year) was very well-attended, but the people we chatted with were mainly tourists who had planned vacations around the festival. University of Denver hosts small touring groups, but there's almost nothing at Boulder in the way of touring dance groups. (It looks like one performance by the Oregon Ballet Theatre is about it for the coming year.)
But living in southern California, I'm used to regions that aren't great at supporting dance. Fortunately, these cities have good airports, so it's possible to head to New York and Washington, DC to see really good stuff a few times a year!
I think the problem isn't that Denver isn't an arts town, but rather the reduced coverage of it. I live in Denver and man, I could go to a dance show or play every night of the week it seems. Additionally, Denver is a model for other cities in arts funding with our SCFD tax. I was able to go to the Performing Arts Convention when it was here a few years ago and everyone was so fascinated by how we fund the arts. SCFD has a website called Scene 3 or something and it is for all the smaller arts groups in Denver. Also, I heard somewhere that Denver has the highest per-capita non-profit groups in the country.
Also, there is a venue problem. Most of the venues are for concerts or booked up years in advance. A music group I was with wanted to play at the Newman Center at DU and we couldn't book the place for a year! Other than that it is like HUGE spaces that seat thousands or small spaces that seat a hundred. In Boulder there is the Dairy Center and they have a couple dance groups and some other stuff. Some people perform at CU at Mackey but that venue has no parking (literally, it's in the middle of campus and there is no street or lot parking) and it kinda big and trashed from the college kids.
Anyway, thought i would jump in.