How big is Claremont? How big is the LA metro area? How big is Elgin compared to Chicago? Provo is maybe half as big as Salt Lake.
When you're in Claremont, and you want a night out, do you stay in Claremont? Do you in Elgin? In Provo, you're more likely to stay local than go up to Salt Lake. As I said, it's geographically more distinct, but there's also a more insular mindset. "Claremont" is a legal entity, and it's a collection of colleges, but it's not much of an entity in peoples' minds. It's just part of the LA metro area, sharing LA's smog. Provo, in contrast, has a separate identity from Salt Lake, and even has separate smog.
Colorado Springs is probably the better example for the argument.
Colorado Springs does. It has a much more independent existence. It's across the Palmer Divide from Denver. It probably depends on the Air Force at least as much as it depends on Denver. In the same way, Provo probably depends on BYU as much as it depends on Salt Lake. (Whereas Elgin and Claremont are much more tied in to Chicago and LA, respectively.)
How many residents of Elgin work in Elgin? I suspect the fraction is much higher in Provo (and Colorado Springs).
And also, as another commenter pointed out, suburbs/exurbs can also be net producers themselves.
> less successful?
That depends on what your criteria for "success" is. San Francisco has among the highest per capita GDP of any city in the Union as well as a thriving technology economy, but also has the highest rate of homelessness, as well as the highest percentage of people living below the poverty line. What does "success" mean?