Boulder has gotten used to topping rankings of startup communities, innovation economies and places to live.

And the Boulder metropolitan statistical area — comprising Boulder County — recently ranked No. 1 nationwide in a ranking by financial-news website 24/7 Wall Street of the nation’s best-educated communities.

But, as writer Curt MacDougall noted in a recent article prepared by BizWest for the Boulder Daily Camera, Boulder has dropped in other rankings, or even fallen off altogether.

The reason? High real estate prices, for one.

The median sales price for a single-family home in the city of Boulder is approaching $1.6 million, among the highest in the entire state.

That’s prompted concern for Boulder Chamber CEO John Tayer, among others, who worry that high housing prices are making it difficult for startups to establish themselves in the city, as attracting a talented workforce is made more difficult if those workers can’t afford to live in the city.

And commercial real estate can also be pricier in Boulder, with institutional investors snapping up office portfolios at exorbitant prices, thereby driving up the cost of office space.

At the same time, Boulder faces far more competition than it once did, not only from less-expensive startup communities that continue to emerge around the country, but also from within Colorado.

Fort Collins, Longmont and Loveland have worked hard to develop their innovation economies and provide both less-expensive housing and more-affordable commercial real estate.

And then there’s Denver. The Mile High City has emerged as a startup and technology mecca in its own right, with far more housing options than exist in Boulder proper. And commercial real estate also is more abundant.

Inc. Magazine recently ranked Denver third in the nation for entrepreneurial activity, reflecting “Surge Cities,” with strong startup ecosystems. Boulder did not make the list.

“A few years ago, we were at the top or near the top of every list of leading startup communities,” Tayer told the Camera, “and we notice that we’re starting to creep down those lists. And that is an indication that some of the key factors that play into what makes a quality, supportive startup and entrepreneurial environment are beginning to get the attention of not just the folks who put those lists together, but even more concerningly, are they beginning to actually impact those who are making decisions about where they may begin to advance their creative endeavors.”

No one is suggesting that Boulder’s startup and innovation economy will disappear. But the rankings — or lack thereof — do bring a note of caution that the city should avoid complacency, and do anything it takes to increase affordable housing and affordable space to accommodate startups.