“Rock star” engineers sometimes work at startups, but usually they work for big companies who can pay them twice the salary and have multiple indoor water polo pools and racquetball courts.
THIS is something the 'startup world' and a lot of people on HN are not aware of. Really, really bad-ass programmers usually work for big corporations for good salaries. Not always, but usually. The reason I mention it is because there is a myth that startups are built with the latest, greatest tech by the brightest minds. Often this just isn't true...many startups are hacked together by inexperienced programmers fresh out of college. Sometimes this works, but often it means that nobody on staff is really a master coder, nobody on staff has ever had to fend off Russian hackers attempting to take down your code at 3 am, nobody on staff has had to deal with thousands of users who wake up one morning, can't log in and no money is coming into the company. These are the battles that most programmers learn in the trenches of big companies, fighting tough battles, fixing complex problems under fire. It's not ideal, but I'm not sure if you can really become battle-hardened without going through real battles with real jobs on the line.
This is what happened at Twitter - when the government came after them because they were getting hacked too often, Twitter went out and hired 'real' programmers and got things working. That's something that gets missed a lot in the 'startup story'.