Your first point is spot on! All I have is a blog, and even I’ve been repeatedly told to start writing a book, because I have the mojo, so to speak. And I judge people my age for writing ordinary books. “Yeah, I’m gonna write much better than that. What I write will matter.”
But I actually feel deflated every time I struggle to write, thinking: “I can’t even decide what to write about. How in heavens will I ever publish a book, let alone a masterpiece?”
Now when I look back at my posts, I can say that none of the relatively better ones were planned to be so. So I guess you just have to keep at it. Keep playing the game, not just because you want to win, but because you love playing.