The whole "open the books" point has been vastly overstated. Look, the players should have known that they had no chance of seeing the books because that's what US labor law says. As my mom always says, it doesn't hurt to ask, or demand under the leverage of decertification, but making public the financials was never the sticking point the NFLPA made it.
It would have been a huge win for the NFLPA if they had leveraged the owners into showing the numbers...as far as I know, that may have been an unprecedented labor negotiation victory. But it was also a shot in the dark. And what would have been accomplished by the owners showing the numbers anyway? Are the players going to give up money if the owners are actually losing? No, of course not. The players are going to work off of the last labor deal either way. The financials are irrelevant in this negotiation. The strongest point of leverage that the players have is the public assumption that every NFL franchise is profitable. They don't want any sort of numbers to get in the way of that leverage.
Furthermore, the NFLPA's own website isn't exactly "showing all the data" either:
NFLLockout.com » What Is This Lockout NOT About?
Their point is in the capped years, players received between 50% and 53% of the NFL revenues (with a salary cap max between 56% and 59% over the same timeframe). Conveniently not listed, the 2010 (or uncapped) figures. Because that information hasn't come in yet. Or doesn't fit the argument they are making. Or something.