Isn't it more of a situation where there's huge, glaring, time parodoxes? They mentioned something similar in the third movie (not going to spoil).

[Ignore any continuity errors in the following paragraph. It is supposed to be a paradox]
If John has some sort of familiarity with Cameron's appearance as a Terminator, much like he had with the older model (the T-101) it would be useful to create a terminator with the appearance of that model sent into the past. Still, in the Future Time before John sends Cameron the Terminator back, John (sympathetic human that he is) brings Allison close into his circle because she physically resembles the terminator Cameron. Skynet makes this connection, and creates a terminator for the purpose of becoming Allison. This Terminator later becomes Cameron after John captures it, and reprograms it. It is then sent into the past, starting the whole cycle.

The paradox being that these two causalities must occur at the same time.


I think I just popped something in my brain...