I think you may need to forget who the author is for a second and reread this.

He admits luck plays a huge role in success [0] (especially if you're using the success of others to measure your own success).

He's saying competing with yourself is the best way to measure success and achieve fulfillment. This probably stems from a lot of people using him as a barometer of success in tech. Comparing yourself to others is a great way to be miserable forever.

[0] "Besides, you only have limited influence on whether you’re going to succeed at whatever you put your mind to. It’s by no means within your exclusive sphere of control. There are so many things that have to come together at the same time. Only a couple of which you own."