I posted this in response on the message board, but felt it deserved a blog post of its own. Feel free to comment and discuss.
It's funny that not until the past two years (last year while injuries ran rampant and this year in a rebuilding year) did anyone ever question Billy Beane. You know why? Because he was winning. And on a budget not even close to his competition in the AL (Angels, Yankees, Red Sox).
While the skepticism is understandable, I think that Billy Beane's "genius status" among MLB general managers is rightly placed. He was named general manager of the Athletics in 1997, and in just a few short years he was able to turn around a team that was was averaging 73 wins a season (.454 pct) into a team that went 664-469 from 2000-2006, a .586 winning percentage (average of 95 wins a season). How many other general managers have done that? Not just that, but he did it with a payroll that was one of the lowest in the majors! The Athletics made the playoffs five times in those seven years, how many other teams made the playoffs that consistently?
Only the Yankees had a higher winning percentage from 2000-2006 and made more playoff appearances, and we all know how tough that was for them with their payroll constraints (sarcasm). The Braves and Cardinals had six playoff appearances in seven years, but fewer wins over that period (and Braves and Cardinals fans can probably speak to their budget comparison to the Athletics better than I can), though you have to admit that they were in the weaker league.
Some might argue that because Billy Beane has not won a World Series it means that he doesn't belong in the upper echelon of MLB GMs. But if you add up the Athletics win totals from 2000-2006 (ranking them 2nd, just a few wins behind the Yankees) it shows that he obviously knows how to give a team the tools they need to win a championship, but it's up to them to perform (and not be injured) during that time.
I would say the simple fact that Billy Beane has built an organization that competes with (and usually beats!) teams spending four and five times as much on payroll puts Billy Beane in pretty exclusive company. I suppose it all depends on how you define genius.