My observation as a coach who has been an observer of Cal over the years:
The culture is very different. This can do a lot as far as guiding the choices, outside of practice, of the individuals on a roster. Complete genetic freaks aside, it is very difficult to live like a top DI distance runner if most of the people around you aren't absolutely committed to doing the same thing.
What does building a culture take? A lot of freaking hours.
Sticking with the "hours" equation, consider this. Building a culture quickly where there was none before might take 2 years. The hours that go into this are the head coach's, but also the assistant coach's, and importantly, the first athletes to buy in. In this way, the hours can pile up exponentially. One coach trying to turn the tide will take longer than 2. Once the tide has turned, it has it's own momentum. The athletes are making it happen themselves. Further, maintaining culture, both while building and once established, requires a constant state of look out for the latest, unpredictable force of distraction that will inevitably spring up on any decent college team.
To get concrete with Cal vs. Boulder. Boulder is first of all a distance focused program, with 3 full-time coaches on staff looking over distance and distance operations/recruiting. I would say all three of these coaches are putting in many hours, with quite a lot of experience backing those hours. They have also had more years to put in those hours, and at this point, are without a doubt in culture maintenance mode.
Cal is a program with technically three full time coaches dealing with distance. However--and again I'm not really connected to the Cal program, but there are certain things that you can pick up-- their associate head coach seems to carry a very large workload. This is great, and she seems to do well by and large. She has certainly had some good development with certain individuals, and she has recruited decently well. But it makes me wonder how many hours toward the culture the head coach devotes. And who has control over the means to build culture (i.e. rules, discipline, final say in recruiting and recruiting strategies--I know none of these particulars, but this could be an issue).
I would also wager the funding for the distance programs at both schools are quite different. Short of how they divide up scholarship allocation, this is publicly available, but I'll leave looking it up for someone else.
My 2 cents.