After you guys are done debating this, go ahead and think about the premium it costs for 5+ WAR players. Here's a hint: you aren't going to win much with a lineup full of mediocre players (1-3 WAR), no matter how cost effective those players are with respect to $/WAR.
And you also have situations where you have the megastar but the rest of your team is crap because you can't afford anyone else. Like you had the Rangers with Arod. As with all things you need balance.
Look at it this way. If you are the Rangers. You could pay Tex the market value and have his given value at the current market value. Or you could trade him for several mlb ready players who will make league min and give your team good on the field value. You can then use that money you would of spent on Tex to sign other market value talent and excellerate your rebuild. Which is what they did. Make no mistake. The Tex trade lead to the Rangers having the window that they did.