On inability, silence, and quantity
On inability You're not as talented as you want to believe you are. You will be in the future, but you're not now. However, I know you want to be at a certain level of skill and value, and until you reach it, you feel as if you're not valuable at all. That's fair—so long as you act on your desire. If it pushes you to learn more and immerse yourself in the areas you want to make an impact in, then your standards have done their job. However, the frustration you feel doesn't seem to be helping. Your goal isn't just to make an impact—even the lowest employee on the totem pole makes an impact, otherwise, they would be fired. It's to make the most impact that you're capable of, but also to be pleased with the impact you bring. So far, you haven't done it. You might not have the ability to, but you're not far off.
On silence In your frustration, it's a good thing that you retreat to silence. The only problem is that it reveals your present state, and if you're not careful, others will take advantage of knowing when you are frustrated and try to put you on edge. Nonetheless, I'm glad to see you taking my advice of not talking. Still, you could be silent earlier. It's logical that in order for your silence in frustration to mean anything, you had been talking beforehand. It precedes all of your failures—so why don't you talk less in the beginning? Especially when you have nothing to say and there is nothing to talk about. In most of your conversations, I heard you say nothing. Nothing of value, nothing worth hearing, and none of it helped you progress. It was an outward expression of your inability to get out of your head. Figure out direction first, and then contemplate whether a conversation will help you get there.
On quantity Though you should be plenty attentive to quality, you also need to keep working and keep your output up. Take a look at Bob Dylan—massive amounts of records and songs, of which many became legendary. Similarly, see Seth Godin's collection of over a dozen books and a daily blog—constant creation. The Beatles performed live so many times that it's hard to quantify how much practice they got, and it made them much, much better. The point is that you have some ideas you want to push to completion, and one at a time, you should churn them out the best you can. For the books you want to create, remember that you can always create a second edition. No worries. You'll learn in the process and the next one will be better.