This video details a specific case of why certain special interest groups have more power over others. There is a lot going on with this psychologically, so let's break down what he's explaining in more generic terms.
A few people can get more done, simply because it's easier to organize. If you have 6 People, and you know the workload level, you know exactly what's at stake if someone doesn't pitch in and help.
If you have 100 people, and even if you know the workload level, you can't guarantee that everyone will do the same amount of work, so splitting the load evenly becomes incredibly difficult. This is why there are so many disconnects in large, corporate companies. This is also the reason Franchises work so well.
Now, I'm not saying that it's impossible to organize a large group of people, however doing so means you have to add specific incentives. Instead of a large chunk of people saying "Oh, There's enough people to get it done, I don't really have to do anything", you need to have them saying "There are a lot of people here, but if I help I can get X thing, so I better help as best I can to ensure I receive it."
This is the main problem with organizing Politics. The incentives aren't necessarily tangible, and the work that is done cannot be tracked and results cannot be seen nearly as easily. It comes down to faith that what work is being done, is helping in the manner intended.
However, there is still something to be said for small groups of people lending a hand where it's needed. Perhaps a better solution to our problems in the country is to get small groups of people together to brain storm possible solutions for problems in their own community.
When every community has the ball rolling for themselves, a collective can come from every community having their lives in order. This is the essentially why our founding fathers placed more importance on Local and State government, as opposed to Federal Government. Because it's harder to organize larger groups, and it's easier for communities to get together and solve their own problems.
No matter your political beliefs, you can agree that it is much easier to get together and talk about solutions with your friends, than it is to go to a town meeting or rally and get possible solutions on the table.