The third argument came to me tonight. Barca play an exciting style that has a defined formation and thus, a way of playing that is uniquely theirs. Even if Barca spent twice as much as any other club in Europe, it would still need to fit those players into a system where they could work together. Thus, its success would depend on good coaching.
The same is true in the NFL and, to a lesser extent, the NBA. If Daniel Snyder were permitted to spend as much as his heart desired, he could assemble a team full of all-stars. However, football being a structured game that requires teamwork, the Redskins would not succeed without smart coaches fitting the players into the right schemes and then calling the right plays. If Washington won the Super Bowl in an uncapped NFL, there would be some criticism, but we would still have to give credit to the team's management for being smart.
What makes baseball fun to analyze statistically is that there is no scheme, style, or teamwork required. The performance of an individual batter against an individual pitcher can be isolated and the outcome can be graded. One doesn't have to take into account whether the player was on a team that played to his strengths because the player's teammates don't matter. The upshot is that there is no skill required in deploying a roster once it has been assembled. Thus, I don't have to give an ounce of credit to the Yankees' management for being smart in any sense other than marketing the team well and squeezing concessions out of the city in connection with the new stadium. The Yankees accumulated a pile of talent because they have more money than any other team and then simply rolled that talent out onto the field. It didn't take much acumen to sign Sabathia, Burnett, and Teixeira in the winter; it didn't take much acumen to put them in their places in the summer and fall. In the end, don't we want to respect our champions for being a little smarter than the rest?