Not only the money, but sacrificing prospects.
If it's "only money" i can see logic in your claim, but when teams have to give up such a substantial amount of payroll flexibility and send young talent in return, then the scenery changes significantly. You also forget that a lot of teams who could have done well for themselves getting both those players (Anaheim and Saint Louis for example) were too tied up retaining their own talent to take on such a significant amount of payroll.
And just money-wise, without prospects involves, i bet than less 10 teams would have been able to absorb both contracts, and out of those 10 teams, at least two of three wouldn't have been able to commit the money and prospects while retaining their own players.
The claim is accurate, because when looking at it in the context of the schematics of the creation of a roster, not everyone has the flexibility to sacrifice prospects, spend money, sign FA's and retain their own talent.
The Yankees do, and it gives them a substantial advantage.