Sorry, but NBA Jam will be better as an exclusive. They can build the game from the ground up to make use of the control system, which just wouldn't work on the other two systems even if they are coming out with their own knock-offs this year. Also, porting costs money and distracts from the main project - leaving it exclusive means it'll get extra attention that it wouldn't as a multi-plat. It also won't have as many competitors on the Wii as the other systems.
The real issue, though, is that it fits the Wii image. You may like your PS3, but it actually lacks a reputation of being fun. A game like NBA Jam just isn't as marketable on the PS3, and like GH (which is to music as Jam is to basketball) it'd end up selling better on the Wii anyway.
Frankly, as it is, some devs complain about games not being worth the effort on PS3 and for the sales they'd probably get it may not be worth it. If the game sells 600k on the PS3 but 500k of those people would have bought it on the Wii, then they aren't making money. It may seem like a lot for a "cheap port" (it wouldn't be, since they'd need a graphical overhaul in addition to recoding in order to pass Sony's standards) to sell over half a million, but when it's taking most of its sales from another system it's not.
Frankly, I applaud EA for this move. They are finally starting to follow Nintendo's plan. The idea is to differentiate your Wii games from other systems in a positive way. Turning Soul Calibur into a bad Dynasty Warriors clone is terrible. Putting simulation basketball on the systems that do realism the best and your arcade basketball on the system that gives the best arcade feel is just plain logical. Yes, Jam would work on the HD systems, but without those add-on controllers it just wouldn't be nearly as fun and without that there's no evidence it'd sell all that well.
You do not have the right to never be offended.
