You need to read or re-read section xxiv of the CBA. It determines what the credits to TR include and how they are calculated (there is no $1B off the top but rather a complicated formula for determining credits annually). You will note throughout references to amounts allowed or approved by the NFLPA as well as the fact that all of those items are audited annually by an independent accounting firm whose cost is shared by the NFL and the NFLPA and whose assumptions which form the basis for the calculation of the salary cap are subject to challenge by the NFLPA, which if upheld carry serious financial penalty.
I understand that the $1B off the top isn't a pegged amount, but the product of a number of credits deducted from TR that has amounted to around $1 billion at the present amount of revenue, representing 11% of gross revenue. Set deductions of fixed percentages account for 6.8% of gross revenue off the top, meaning that over 60% of the off-the-top money is not subject to independent auditing.
The rest of the credits are included as deductions in revenue reports, and are reviewed by the independent accountants only to the extent the type of expense being deducted is in accordance with provisions in the CBA delineating what expenses are deductible from TR. The reports of these deductions are made in confidence, and
not subject to NFLPA review. The only oversight the NFLPA has on the deduction process is if the NFL wants to add a whole new category of deduction.
A decision some visionary owners supported even at their own expense to pool national TV revenue in order to achieve a level of relative competitive parity foreign to other sports and market the game and the league as opposed to the transient talent and the stability and consistency of product (games) that has facilitated has had as much to do with the growth in value of these franchises as has the performance of the talent on the field on any given Sunday. In this team sport strategic decisions owners make individually as well as collectively where investment in coaching and management and player personnel selection and marketing impacts the valuation of franchises at least as much as talent does. Winning doesn't even necessarily impact valuations, or the Cowboys and Redskins and Texans wouldn't be among the top 5 franchises in value over the last decade...
Following the 2009 season for the first time since Forbes started tracking franchise values in the late 90's team values league wide fell 2%. Two-thirds of teams lost value, including three to the tune of double digits. Forbes attributes their valuations into Sport (value relative to shared revenue), Market (size), Stadium (deal) and Brand Management. They do not attribute any of that value to Talent, which on average turns over at the rate of about 20% per year. The NFL is something of an assetless entity since it's stadiums have limited use and most still aren't even owned they are leased.
It wasn't the owners who were the visionaries behind the revenue-sharing plan, it was Pete Rozelle. The owners were only convinced because at that point, TV revenue wasn't really a big part of their revenues. The purpose wasn't competitive parity, either -- it was bargaining leverage with the TV networks. If the networks wanted the rights to NY, Chicago and Dallas teams, they'd have to pay for the rights to the smaller market teams' games, too. Not only did this secure for the NFL more total money than teams would have been able to negotiate individually, but it also ensured that all the franchises would be able to get on TV at all, which was key in terms of helping new and struggling franchises grow their fanbase.
But all that history is kind of besides the point, anyway -- who is responsible for coming up with the best ways of maximizing revenue is an entirely academic question, because without the performance of players on the football field, there is simply no product to be sold. The players' contribution to their team goes beyond determining who wins the game -- their performance is what people pay to see. That's why all of the revenues comprising TR in the CBA are considered, by definition, to be those "arising from the performance of players in NFL football games."
As for the transient nature of the "talent" in football - that's why the owners aren't interested in any plan that compensates the players with equity in the league or teams, the way Google and Apple attract talented programers and designers by offering shares in the company in addition to salary. This was suggested during negotiations as means of geting the players to agree to more deductions from their share of revenue for league growth, promptly rejected by the owners, and dropped by the players.
So, you're correct, Forbes doesn't factor talent into its valuation of NFL franchises because that talent, as you point out, is transient. Nobody buying an NFL franchise is going to consider how good the players are that particular season, because that will fluctuate from season to season. But while the value of the individual franchises isn't derived from the talent of its players, the value of the NFL's product as a whole is, entirely. And as a franchise only derives its value from being part of the NFL, all of its other assets are derived from the performance of the NFL's players in football games.
And your contention that any owner who has owned his team for more than 10 years now has tripled his investment is simply incorrect. Even Snyder has barely doubled his investment in the last 12 years. McNair, Woody, Bisciotti, Werner haven't yet achieved that rate of growth. And it doesn't look as if Blank or Wilf will even approach that and it's entirely possible Ross never will (the Dolphins value hasn't changed in the 3 years he's owned them although their debt has certainly increased).
I'll have to get back to you on this, when I've been able to track down where I read this, and check the math.