I would have thought the opposite. The more attempts I can make, the more I can play the odds, regardless of risk. If I only have a few tries, I'm going to want to take a less risky position.
I look at it this way. Everyone's career is a baseball game. Most workers get 5 or 6 at-bats throughout their lives, and can afford to just go for base hits. A tech worker gets 1 or 2 at-bats so he has to swing for the home run if he wants to score.
Notice that many of the arguments presented here about why younger workers are favored would equally apply in more conservative professional fields, like law - it's certainly not the 50y old partners doing all-nighters on a regular basis. But there does seem to be a certain level of inter-generational respect among lawyers that is absent in tech. Why, I don't know.