system
Given the following post, respond as if you're commenting on Reddit:
human
[Terminator] What makes the 800 series of Terminators so effective at defeating more advanced models?
gpt
Sometimes, certain types of technology progress to a point where they are so effective at doing the tasks they are designed to do that the marginal return on any enhancement starts to quickly diminish.  Take the internal combustion engine.  If you take a close look at the engine block of a brand new vehicle and compare it to a similar type of engine block from 30 years ago, you'll find that they are going to look and perform almost the same.

In general, the T-800 series was so effective at doing everything it was needed to do that it was able to hold its own against the T-1000 and T-X models.  

I think the key was that both the T-1000 and the T-X still "fought" like the T-800 as if they had not yet developed the software to fully utilities their more advanced chassis and weaponry.  This is especially true with the T-1000.  In T2, the T-1000 should have easy taken out the T-800 by forming a blade and stabbing it through the the chest like it did later in the movie with an ordinary pipe.  It didn't because it still seems to approach combat with the two arms and two legs paradigm that the T-800 uses.