Yes and no.
Deferred money on its own isn't a competitive advantage. The time value of money stuff sees to that.
However, some players have taken to heavily deferring contracts with the intent to move to a state without income tax prior to the big money coming in. In essence, they're dodging taxes on it.
Many expect those States such as CA being exploited by these contracts to patch their loopholes and demand state income tax based on the time the service was rendered rather than the time the money is paid. But right now, when offering deferred money, the teams in those states are also treated like FL and TX and other states without state income tax. That's a competitive advantage, surely.
I'm not sure what our tax laws look like. But if the same scheme is theoretically viable in IL then it would constitute a competitive advantage to offer income that will not be taxed by the State. Although, TBH, as a taxpayer, I'd be somewhat upset if they were taking advantage of it.