I also agree with Steve Jobs, and with you when you say that you have to "understand as a fact that".

For me it's enough to see someone that is doing it. If he can do it, I also can.

But I think there is also something related with imagination, knowledge, learnings. I cannot imagine the infrastructure a 100M business requires. I guess that is why so many ex-googlers or ex-amazon, after quitting, build great things. They have seen it before.