You've made quite the interesting observation.
Some people want to invest their funds, time, or both towards an investment. What I see in the rich list of any community is a level of commitment they have towards the token. This type of list could help someone gauge whether or not to make their own financial commitment.
The rich list, in no way, is a measure of activity on the platform. I don't think it can ever be as most of the work involved with community development will be behind the scenes. I equate it to being similar to construction. You'll never see the planning, development, reviews or any of the thousands of hours of activity that goes into the project before people see it.
If the work is significant enough, then it will enter your view screen of your mind. Until then, it will remain essentially invisible to the surrounding world.