We compare ourselves with our perceived peer-group. But we tend to self-select peer groups that are not too far from our own level. On the other hand, most of us looks to role models, which are pretty much by definition more successful than ourselves.
We rarely compare ourselves to the people we consider we've already firmly surpassed. We might hang out with existing friends that we feel we're more successful than, but we're trying to meet that new potential employer that's above where we think we'll go next; we're trying to hook that huge important client; we're more eager to network with people we see as hugely successful; we want to learn from the people we consider smarter than ourselves, and so on.
Not only that, but outside our own circle, the successful people are far more visible. For every successful founder there are hundreds that failed, gave up, never even got a company funded, and so on that we will never hear about.
I've been through several startups. Some I co-founded. Others where I was the first guy or first 2-3 people brought in, on substantial equity. Been involved in a number of VC deals. But no big exits. Nothing enough to retire on. Not paid of my mortgage.
It'd be easy for me to write a similar post about my career. Lots of companies that could've, should've made it big.
Yet, years ago I realized that the moment I founded my first company, I was more successful as a founder or "startup guy" than most people - most people who want to start a company never even try, and fewer succeed. Each subsequent one, I've left some mark or other. So I've not founded another Google. But I've done enough. I want to do more. Lots more. But I've still done enough that I have plenty to be proud of without feeling a need for everyone to know about it.
(though he things I'm the most proud of these days no longer have anything to do with my work at all)