I don't think you can conclude that because "young entrepreneurs are asking for NDAs more than older ones" that the older guys are successful due to their openn

I don't think you can conclude that because "young entrepreneurs are asking for NDAs more than older ones" that the older guys are successful due to their openness, or by talking about it it creates a buzz that makes it successful. When you're young, inexperienced, and (most importantly) have a limited business network it is much harder to execute on an idea. A successful older person has a trusted network that they can approach with their ideas, and therefore worry less about NDAs. Younger people -- and those with less experience -- are often cold contacting angels, or setting up meetings with potential investors they have had very short business relationships with. The potential investor probably won't steal their amazing idea, but the process of starting up is much more difficult and the time cycle of idea to launch could be significantly longer for this group of people than those with experience, which could explain the paranoia. I'd expect those with a smaller, less "powerful" network to more often ask for NDAs on new ventures, regardless of age.