It's thinking along the lines of that which underpins fan support for team salary caps. The belief is that it will level the playing field among teams. Assuming whatever new salary cap is going to be roughly the same as next year's CBT amount, which is $244 million, at least 25 teams are already under that. And even if they set the first team salary cap at something drastically low—say, $150 million per team—the active payrolls of 20 teams are still under that. Most organizations are already hamstringing themselves when it comes to signing top talent. What makes us think these teams are all of a sudden going to spend a lot more once a cap is in place?
Besides, even if by some unrealistic assumption the bottom feeders were to start spending under such a cap system, once the money is capped by team—once the top offers coming from places like Los Angeles and New York and Chicago versus Kansas City and Milwaukee and Pittsburgh are essentially the same—then the difference in money offered becomes less important, and other factors both hard (Which teams are going to win this year?) and soft (Which cities would my wife want to live? Where can I get the most national visibility and build my personal brand?) becomes more important.
And this doesn't even contemplate whether it's fair and equitable that a team that generates way way more revenue, like the Yankees and Dodgers, should be held to the same hard spend caps that the Rays or Marlins are.