It's not that they can get away with wearing jeans so much as they can't get away with wearing other things. There's still an egalitarian and meritocratic notion in technology that rank shouldn't matter. Ask yourself why NSA director and General Keith Alexander showed up at DEFCON in jeans and a t-shirt with an EFF logo on it.
Most of these guys telling you what to do, where to live and which technologies or schools that matter are Ivy League alumni multimillionaires. Many from a time before a widespread Internet and grants for poor students. When was the last time you saw any of them sit down with someone who were really challenging their views?
Edit: For somewhat of an example of the last thing there are two episodes of This Week In Startups with DHH.
Most of these guys telling you what to do, where to live and which technologies or schools that matter are Ivy League alumni multimillionaires. Many from a time before a widespread Internet and grants for poor students. When was the last time you saw any of them sit down with someone who were really challenging their views?
Edit: For somewhat of an example of the last thing there are two episodes of This Week In Startups with DHH.
https://www.youtube.com/watch?v=XDGHxO6N3Ms&t=15m30s https://www.youtube.com/watch?v=jzERXJgi5vQ&t=7m11s