[bomatson]

I can appreciate this insight on Zynga, but I'd like to offer another perspective:

First off, have you seen the way Blizzard's stock performed during 2008? It was one of the few that continued to grow...

Rovio has more than just Angry Birds direct sales, it has a TON of merchandising opportunities with the characters (think Pixar). Plus they have a huge base of users that is excited to see what's next.

I'd also contend the rock stars analogy is backward - It is FAR more risky to assume a sole person can continue re-inventing themselves over a entire career. Granted, it's hard for game publishers, but at least there's a team and a more defined process for the innovation.