Wrong question, so wrong answer.
Right question: What is the value and cost of a Lombardi Trophy?
Kraft has answered it and said it is "... to spend up the amount the league allows per year and not more. And remain competitive every year". So let them spend it.
Having an "insurance policy" for the most important position on a football team, for a legitimate Super Bowl FAVORITE, by Las Vegas, makes pure sense to me.
I've already said in another post why this is purely a hypothetical exercise. What the OP is asking, as far as I can tell, is how would one determine Cassel's theoretical value, absent a market that, in the real world, actually does determine that value (even the tag is based on a market basket of contemporary salaries at any given position). As far as I can see, that's a fair question to ask. It might not be particularly useful or have any practical implications whatsoever, but it's an interesting way to think about the salary subject in February, between the SB, Combines and Draft Day.
You raise another interesting question.
What is a Lombardi Trophy worth? I wonder if anyone has ever put a monetary value on a SB victory.
Teams get the bulk of their revenues from Broadcast rights, based on a contract that doesn't care whether a team is 16--0 or 0--16. The Steelers will get the same amount under the contract next year as they would have had they not gotten near to Tampa. There might be an uptick in Season Ticket sales among teams that are not already sold out (it would be interesting to see what happens in Arizona after the SB run), but I doubt that is that great. There might be an increase in promotional and ancillary sales, but that also is probably not that great.
The only real way to measure this would be in the increase in a Franchise's value after winning an SB. Anecdotally, the Patriots' franchise value has trebled or quadrupled since the Krafts bought the team. It would be an interesting Valuation exercise to try to attribute a portion of this increase to SB wins and not just to the overal inflation of all franchises due to the sport's popularity and mega Broadcast Contracts. I do, however, suspect that is real, but, since there is no public market for nearly all NFL teams, it's difficult to quantify beyond the annual Forbes stab at it.
If I look at the top five Franchises by Franchise Value and the last three SB Winners on the most recent Forbes list that I have (I doubt it changes that much and there are clearly other factors at play here, including Real Estate and Stadium values, but it's the best we've got before deeper analysis) and compare it to SB wins, this is what you see:
1) Redskins, Total SB Wins 3, last win 1991 season
2) Patriots, Total SB Wins 3, last win 2004
3) Cowboys, Total SB Wins 5, last win 1995
4) Texans, Total SB Wins 0, last win never
5) Eagles, Total SB wins 0, last win never
15) Giants, Total SB wins 3, last win 2007
18) Steelers, Total SB wins 6, last win 2008
22) Colts, Total SB wins 2, last win 2006
One can't just argue that a Lombardi is "priceless" and therefore worth any reasonable price to obtain one. Otherwise, owners would behave differently than they actually do. Clearly, teams take different views of this.
Some spend and manage themselves consistently to be competitive for the Playoffs year in and year out, like the Pats and Steelers and Cowboys and Colts and several others. The very fact that Bob Kraft feels the need to state that objective suggests that it is not a universally shared objective among NFL owners. Otherwise, saying that "We want our team to be highly competitive for the Playoffs year after year" would be the same as saying "Our team is going to play football."
Other teams, like the Vikings, Cards (until this year), Chiefs (in recent years during Mr. Hunt's illness) and others, seem to go for extended periods without particularly caring about the quality of the team that they field. They are content to field a respectable team but don't seem particularly driven to get to the Playoffs, let alone the SB. The Broadcast, Gate and Ancillary revenues seem to be enough for them year in and year out as an annuity without a lot of investment.