I don't think any of your points really hold water. Even a world in which ideas are worth equally as much as execution would make no sense. I can't fly to work in a picture of a flying car; the execution for new vehicles hasn't gotten any cheaper or there would be more novelty car companies. I can't network with my friends using Diaspora. If execution were so easy, there should be ten decentralized Facebook clones with proper privacy guarantees by now, and there aren't. Spend four hours walking around, wherever you are, and you can find a dozen or more people convinced they have brilliant web ideas they just don't know how to execute. Everyone who can't program is an "idea man." Separating terrible ideas from the rest isn't hard, but without time travel it's impossible to distinguish decent ideas from extraordinary ones.

The Valley is becoming more and more insular and self-referencing. From outside, where I am, it looks to me like a mirror of the setup for the housing bubble, where the value of everything today is zero and the value of everything tomorrow is infinite, so nobody is doing anything today except trading the possibility of doing more and better things tomorrow. An idea or a founder might be worth a lot in this environment right now, but I don't think this situation is sustainable.