I don't think it's talent nor confidence. LP just works differently than other bands. Take Julien-K for example, since a lot of us know about them. Their process seems to be this:
1. Create song idea.
2. Work on song for a while.
3. Once it is a rough song, with vocals and instruments, call it a demo, move on to a new song.
It seems like JK does that process with a couple songs at a time. LP's process seems to be this:
1. Create song idea.
2. Track a rough version (like "Oh No" the PoA demo)
3. Move on and start a new demo.
LP seems to kind of have a bit of a musical ADD if their process is the way it seems. Instead of doing the JK process of developing a few ideas into "full" demos, LP keeps their demos very rough, and keeps bouncing from idea to idea.
Starting with A Thousand Suns though, LP started to take on a bit more of the JK process. As Mike said on his blog, they would separate some of their demos into "batches," and then work on those couple songs extensively.
So basically, it has nothing to do with talent or creativity, they just have a different way of going about things.
And as for Mike being the creative force in LP, it is true, it does seem like he creates a lot of the demo ideas. But Chester is no slouch either. And after seeing the ATS process, Brad plays a bigger role than I had originally realized.