I've blogged about the beer industry before, here and here and here. In these posts I've argued that because of economies of scale, the beer industry tends to evolve towards one dominant producer, which enjoys a large moat around its business and is able to earn excellent returns, make its founders rich, etc.
I've been trying to collect counterexamples--instances of a dominant beer losing its number one position and why that happened. Per Wikipedia, Fix beer used to be the only beer widely available in Greece until that market was opened up to foreign competition in the 1960s, beginning a decline that ended when the Fix brewery was nationalized in the early 1980s. A friend informs me that until quite recently Singha beer was the dominant beer in Thailand, before Thai Bev launched Chang.
Here's one account of how Schlitz, which used to be the top-selling beer in the U.S., lost its position. If true, then to me it's further evidence of how difficult it is to dislodge a number one beer--you really need to screw things up badly.