Not entirely. Look at Oprah. But on a general level, yes.
Exception or the rule?
Based on a single 1-in-a billion anecdote, yes. It certainly does seem that way.
The odds of this natural experiment happening at all were quite low, but surely you don't mean to imply that the outcome we have observed would be very unlikely to occur again if the experiment was repeated. I would expect many of the results to be similar to this (in the hypothetical situation where this unethical experiment was done numerous times). Our environments shape us immensely.