We hear Pareto's Principle invoked all the time as if it is something universal and beyond our control.
What if it's not?
What if the these percentages are not because of some predetermined tendency of the way individuals act, but is instead a logical result of the systems and processes we put into place?
When looking at situations from a system thinking perspective, you go beyond the events visible at the surface to dig deeper in search of the patterns producing them and the structural source of the pattern.
So the next time you lament and accept the lack of participation in a program or the small corp of volunteers doing the heavy lifting on a project, look to see what principles or practices you've put into place that might be leading to those very results.
You might just find that 80% of your systems are focused on enabling only 20% of your potential participants or contributors. Your problem may not be the people, but instead your processes.