Everyone should play his role. Everyone will play his role in changing the world. Making impact, changing things, making differences is not easy but it is actually simple, simpler that we think. If we think about one person who will change the world for the better as we always thought, it's not going to happen and the change is going to be impossible as it has always been, in our heads.
It's as simple as making a small change with the idea you care about, you will change people and these people will change others. The impact is going to grow far more than you think.
It's easy to be motivated to spread the idea more and more so more people will know about it, you may think that trying to convince more people who aren't interested in getting the change you offer but that's not how the change can be made.
Reach the people who believe what you believe, change those with the thing that you're building. I can't change my country by being the president so I can control more and try to improve a lot of things at the same time.
In the age we're living in, you're more powerful that a president by leading a small tribe who believe what you believe, that will spread the change you affected them with with the thing that you've built.
Everyone plays his role, so stick with that one thing you want to change in your town, your country or in the world, fight for it, do it for that tribe and that will be your role in easing lives for little or many people, just make the change.