Nissan won't do anything but it's fun to speculate. Like others have already commented, there's practically 0 direct competition for the 370z. I might even go far enough to say it's the fastest, nicest, most option-able sports car (not to mention about the ONLY SPORTS CAR) in it's price range.
I actually had someone try to compare a newer Z4 (i6 twin turbo model) with the 370z saying that they're pretty similar... all I did was laugh and point out the fact that even the Nismo 370z is about $6k cheaper than the Z4 and people looking at the Nismo probably didn't even think twice about the Z4.
Maybe we should take a poll for all the people who cross-shopped the 370z and z4. Alright, I counted 0. What'd you guys get?