This is an aspect of entrepreneurship that I haven't thought much about. I think you make some excellent points; not only do you need a great idea but you also need to have the right timing. Even great ideas can fizzle and go nowhere if the world isn't ready for them.
Another characteristic of entrepreneurs is the ability to cope gracefully with failure. I think the commonly accepted wisdom is that 9 out of 10 startups will fail. But when that happens you just pick yourself right back up and keep on going, looking for that one success that makes it all worthwhile. Failures teach valuable lessons that are hard to gain any other way.
You can view Steemit as a microcosm of entrepreneurship. To be successful on here requires many of the same attributes as a successful entrepreneur: you need persistence, good ideas to write about, good timing, and a refusal to get discouraged and give up if a particular post (or whole string of them) ends up being a total flop.
I loved the whole comment, but the last part.. You just killed it! Spot on! It's like any other part of life, even actors and musicians have to persist in real life, not just writers and start ups. In steemit, many of us try to help people with the steem guild and Curie, and other projects, but the rules of life apply here as well. Perseverance as you said, is one of them.