If our standard is either a team wins a championship or it’s a failure, then I suppose you have an argument.

The following quote about Peyton Manning’s lack of Superbowl victories states my argument better than I can:

“His teams often had critical shortcomings that were exposed in the playoffs. Lack of a running game, porous defense and undersized defensive line are just some of the issues.
An elite QB can mask these deficiencies a lot during the regular season, but once you are in the playoffs, teams tend to be the best in the league that year and more focused on the upcoming game. Seldom are they looking past their next opponent to the next round.
In these cases, when your key need is to shutdown just one part of the offence- the passing game- and to exploit the overt weaknesses of the defense, good coaches of more well-rounded teams can design schemes that do that very well.”

In the NBA it happens frequently that an overpaid star like Amar’e Stoudemire prevents the acquisition of quality depth.

Conversely the Seahawks were able to take advantage of rookie contracts for highly productive players in normally expensive positions (ex. quarterback and cornerback) which allowed them to have the deepest team in the league.