Offer more video cards. It's difficult to justify spending that much money on something that isn't going to last me. Otherwise i'd buy one in a heartbeat.
They just did that. If you're in the market for bleeding edge gaming, you're not in the market for a Mac. It's going to be that way for the foreseeable future.
You're missing the point.
No, I'm telling you that the components that go into an iMac are different than those that go into a Mac Pro. No nvidia chipset = no Core i CPU plus nvidia GPU. Intel's lawsuit does not prevent an nvidia GPU from being used with an Intel chipset, but Apple specifically migrated to nvidia chipsets with their last product refresh. Ergo, problem.
The macbooks graphics are integrated. It's a different situation
Again: the iMac is engineered internally like a notebook. The iMac and the MacBook (Pro) lines are similar. The iMac and the Mac Pro lines are not.
Why the nvidia GTX mobility cards!
The 4850, either desktop or Mobility, outperforms the GTX 260M. I haven't seen final benchmarks on the 280M, but I'm pretty sure the heat output would be a bigger negative than the performance bump would be a plus.