It's a problem in a lot of engineering fields. Even when older engineers stay around, the knowledge often isn't transmitted. Sometimes it's because you have gaps, where a company grew a lot, then plateaued with no new hires for a while, then grew again later. That gives you old and young cohorts. Not to be an old fogey, because the young engineers bring a lot to the table too, especially familiarity with newer technologies. But a lot of knowledge slips through the cracks. I'd imagine it would just slip faster when people retire in their 30s.
Might be worse in tech because you can reinvent the wheel, with less physical infrastructure that has to stay around. Or maybe that makes it better. I started writing up something about some of my experiences with institutional amnesia causing problems when you still have the old wheel around, since old factories don't go away easily. But it ballooned into a much longer story so I threw it up somewhere anonymous and submitted separately: http://news.ycombinator.com/item?id=3311015