SO is slowly driving away the more senior participants who haven't been drawn in by the gamification of the site. Every few months it seems like the questions on the site are more and more of the "I could have googled this but it was faster to ask it on SO." variety.
In short, SO is becoming a Mechanical Turk for searching for answers to software questions, and the reason is because Google is becoming less and less useful (as it tries to be more and more helpful) for searching for answers to software questions.
I don't know how that fits into the long-term goals of SO.
I think SO will be happy if they will be able to become a database for most common programming problems.
That is where the crowd is, mediocre programmers are plenty and they won't be asking expert questions either. They need hand holding at every step. And if you could answer all they question they have, you could serve a huge crowd.
On other hand, asking expert questions may make you an awesome site. But the target audience is to little.
Because number of people needing answers to expert questions themselves are scanty.
In short, SO is becoming a Mechanical Turk for searching for answers to software questions, and the reason is because Google is becoming less and less useful (as it tries to be more and more helpful) for searching for answers to software questions.
I don't know how that fits into the long-term goals of SO.