If there was no difference between the success factors or chance factors, then those 5 highest spending teams would be closer to the norm, so there is at least a perceived advantage to spending all that money.
The Rays and the Athletics draft very well, the Athletics can turn regular guys into above average pitchers.
The bigger teams in question often have to send draft picks for signing free agents.
Let's face it, the Tigers are underachieving, the Mets are as well. The Yankees have horrible starting pitching.
They didn't address it, they could have, but they wanted to resign Rodriguez, a guy they really didn't need.
It's true that you can't buy a championship, but you can buy those lottery balls that increase your odds greatly.
If high salaries really didn't buy you any advantage, they wouldn't be around.