Open space is a civic improvement. It happens to limit growth, space being finite. I didn't mention the tax code, but the willingness, and ability, of the residents, to tax themselves for things like open space, which, incidentally, is used by people from a much wider area than Boulder itself (though some of them complain bitterly at being expected to pay to park, even though they pay no taxes here). If you like places with unrestricted growth policies, let me suggest Colorado Springs which has seemingly embraced the notion of expanding infinitely. Different parts of Colorado Springs, however, resemble each other in name only. There's no free lunch.