Why I’m not a founder

Ben Bleikamp, a designer with a very respectable and enviable design career:

I respect founders immensely—I’ve worked for them my entire career. But me not founding a company is not a question of risk, a lack of ideas, or that I don’t want to change the world. I simply value other parts of my career more.

If you find the right group that’s well established and a fun place to be (culture, again) then why isn’t that seen as a success? Why must everyone be entrepreneurs to be successful?