I don’t think there is either. And I certainly grant you that keeping players through their early years, when they’re cheap, is a valuable and important strategy. And maybe Beane raised this strategy to an art form, I don’t know.
But it certainly wasn’t a brand new strategy, and it doesn’t seem like a particularly revolutionary strategy either–it seems like something any decently-run money-challenged team would do. In fact, there are plenty of players since the free agency era who were kept by their teams only as long as they were relatively cheap; when arbitration or free agency arrived, they were gone. Lots of these guys predate Moneyball.
Here’s one example: the Pirates of the early nineties. Over just a few years they got rid of a whole host of players when they hit 5-7 years of service time, notably Barry Bonds, Doug Drabek, Jose Lind, Denny Neagle, John Smiley, and Bobby Bonilla. Some left via trades for younger, lower-priced players, some to free agency. In fact, IIRC, about the only young player the Bucs kept during this period was Jeff King.
The Pirates at the time were a very fine team that like the Athletics ten-fifteen years later never did manage to make the World Series; eventually, again like the A’s, they ran out of good players in the pipeline, sustained constant bleeding of the players they had developed or traded for when they were young, and became a sub-.500 team. (Actually, I never noticed the parallels before. I’ll add to that that King was a 3B, as was Eric Chavez, the only big player the A’s kept.) In terms of using players as long as you can afford them, then, and letting them go when they get too expensive, there’s plenty of history before Beane was a GM. And again, it just doesn’t seem like a Plan of Genius.
And I understand your argument that San Diego didn’t much want Zito, but I’d still say that anyone who is drafted ninth in all of baseball is somebody who is quite well regarded (even if maybe not by the Padres). Think about it: if the A’s didn’t think someone would’ve grabbed him later in the round, why waste a first round pick on him? Take someone with that first pick that you’ll miss out on later if you wait, and go for Zito with your second or third-rounder. Or, if he’s really that poorly regarded, wait till his name comes up in the tenth round or the twentieth. That would seem like Billy Beane strategy to me–don’t just take the guy you want, take the guy you want when it’s to your best advantage to do so. And even if Zito didn’t get a contract offer that suited him when Texas picked him in round 3 a little earlier, being picked in that round puts him in the top 75 or so amateur prospects that year–that’s pretty decent.
So, if your point is, Not everybody wanted Zito as badly as the A’s did, that’s probably true and I’ll happily concede it. If your argument is, Nobody else really wanted him, well, the evidence doesn’t support that.