Of course money up front is worth more than deferred money but the trend is becoming pretty pronounced among the top free agents and highest-spending teams, and that's where the Phillies are trying to be. The Dodgers now have more than $1 billion in deferrals to 1/3 of their roster between 2028 and 2046. The numbers get bigger later so they aren't even on the hook for that much escrow those first few years, and their position is they will actually make money on that since it can be invested.
The loophole thing is also sort of unique to baseball's part-time and travel-dependent salary system. If they were paid 12 months of the year instead of just in-season, the guys who live in Texas or Florida would pay less tax in PA and on the road. But they are very specifically paid for x number of days in PA and x number of days in all the other states (and not at all in spring training either).
I would think the loophole is a lot bigger than sports. Probably lots of CEOs do it too (and/or they are deferring money into non-taxable retirement). And let's face it, not many politicians interested in taxing the rich more, even if a state like California would like to get their hands on some of that dough.
This will come up again in the CBA I'm sure though seems like both sides have bigger fish to fry.
