The real problem was Terminator was never supposed to get a sequel in the first place.. It dealt with time travel, it was a one off. Everything included T2 fukked up the explanation to a lot of things.
In T1, when Reese is talking to the doctor, he explains they already won. The Terminator was sent back first as a last ditch effort, then Reese to stop it, then they blew up the time machine. He was all that was left..
But it made so much money, they had to come back.. Then all the sudden, Skynet sent another more advanced Terminator. How they do that when it was already over for them, and they just debuted the T-800? Ok then John sent back a reprogrammed old Terminator to stop the new one. Where'd he get that and how'd it send it back? They blew up the lab.
Then it goes on to more nonsense to keep explaining how they keep doing the same thing every time. How is the enemy and the resistance both keep sending back their people, but nobody blows up the machine. If Skynet built more, then they would be sending back more than one, and the..............
Nevermind.. But you get the point
Dr. Peter Silberman : [in a interrogation room inside the police station] Why this elaborate scheme with the Terminator?
Kyle Reese : It had no choice. Their defense grid was smashed. We'd won. Taking out Connor then would make no difference. Skynet had to wipe out his entire existence!
Dr. Peter Silberman : Is that when you captured the lab complex and found the, uh, what was it called... the time displacement equipment?
Kyle Reese : That's right. The Terminator had already gone through. Connor sent me to intercept him and they blew the whole place.
Dr. Peter Silberman : Well, how are you supposed to get back?
Kyle Reese : I can't. Nobody goes home. Nobody else comes through. It's just him - and me.
