Indeed your post made me think anotherthing, because you made a very good point. I have never before considered the fact that people switching units can have 400 hours logged already, quite few hours!
When I say emergencies I do not mainly think of crashes anymore. Even though they occur, when I'm asked what I consider to be the worst possible scenario I usually answer: "a complete radio failure during peak hour". Sure crashes are horrific, but from my outside perspective the thought of a complete radar failure is a lot worse. But maybe that's a view not shared by active ATCOs?
But it seems we're going to the conclusion that given enough time anyone (or almost anyone) could be trained as an ATCO, just as they could be trained to become doctors, engineers or any other occupation.
Maybe I put to much emphasis on the fact that controllers must keep calm in an emergency, after all (as has been said in this thread), the majority of the work involves no emergencies.