The people who accomplish the most are never satisfied with how much they have accomplished. Series of accomplishments require continuous accomplishing, which requires motivation. These high-achievers continue to accomplish so much because they constantly motivate themselves with thoughts of inadequacy. I assume most people only follow others who they see as more accomplished than themselves in some way. By definition you must follow someone in order to compare yourself to them. Thus, you must only compare yourself to people more accomplished than you. By doing do, you promote in yourself the same feelings of inadequacy that drive thr most acccomplished people.
tl;dr Compare your accomplishments to greater accomplishments by other people. Feelings of inadequacy will motivate you to accomplish more.
If you look at some of the most successful people, most of them are driven by other motivators besides success. Many are driven to make a difference in the world (Steve Jobs, Elon Musk, etc), others were super super curious (Richard Feynmann, Neil Degrasse Tyson, Warren Buffett) and pursued / stuck with their passions, and others were at the right place at the right time (and of course people are often some combo of all 3). The thing is, very few people just are addicted to success for the SAKE of success, and some of those people have an unhealthy addiction for money. Success is what you make of it. There are many people in the energy sector driven to eradicate global warming and get off our fossil fuel addiction. Many of them will be never known to the world / famous in any way, but they are always looking to make more and more of an impact daily and be successful over time (even if many of them won't ever be rich or famous).
I think many people are seeking success for success' sake - at least it's a significant part of why they do what they do. The fact that they want to make a difference in the world may be true, but I think it's often a mix, and that people fool themselves to believe that their need to feed their ego is smaller than it actually is. The risk from this, is that although people are fighting for a good cause, their ego may interfere in bad ways in certain situations, leading to decisions and actions which hurts the good cause in short or long term (for example by pushing away other people who may do a better job than themselves).
(This, of course, doesn't go for everybody.)
Edit: Note that becoming rich and famous isn't the only way to feed your ego.
tl;dr Compare your accomplishments to greater accomplishments by other people. Feelings of inadequacy will motivate you to accomplish more.