Many of them turn out not to be marketable, though, and that doesn't necessarily count against you. It's not the high-order bit—the high order bit is the founders. Ideas can and do change.
I saw another post here about this book a few months ago and gave it a shot. I lasted about four weeks before giving up on it. I found the process of writing morning pages to be thoroughly unpleasant and it did nothing to spark any creativity in me. I also found the premise of 'someone in your past told you not to be creative' pretty hard to relate to.
Similar to meditation, really. My experience seems at odds with everyone else and I'm clearly the weirdo for not getting anything out of it.
Meditation is a good analogy. I haven't found sitting and meditating for 15-30 minutes especially mind-expanding. Listening to music and walking my dogs, however, sometimes takes me somewhere expansive. That is to say, I don't think there's a one-size-fits-all rule here. More like we should experiment with ourselves and our patterns, and that we can use the signs left behind by fellow travelers as a cue to look more closely in certain areas.
With all that said, 1) I don't think it's important to literally write "morning pages" (nor does Ms. Cameron, in my reading). It's important to find the correct medium _for you_ that manifests ideas in the world. 2) I think the signal-response pattern _is important_. It's not enough to put thoughts/feelings/whatever into the world. You need some means for things to return to you.
Flip it around though, as a fellow weirdo -- what stimulates your creativity?
Seems like most of the application is describing your idea.