I was curious about this - if my Google results are accurate, it looks like the stock actually peaked in June 2007, the same month that the iphone was released.
It seems that Blackberry's market share of new phone sales peaked at 20% in 2009. So I'm not sure if it's coincidence, but it looks like the market actually did a pretty good job of pricing in the iphone/android risk well before it was strongly reflected in sales.