I get the impression that you didn't really read my post. A theorist does what Einstein, Hawking, Kaluza, Klein, etc. did. They look at things that they know, that they can observe, then they try to draw conclusions about the deeper meaning. Don't try to interpret this as me equating experiment and theory, as I am definitely not.
Theory is when Einstein says, "You know, I'm pretty darn sure that light moves at a constant speed for all observers, and I'm also pretty sure that the laws of physics are the same in all inertial frames. From this, I can deduce the fact that your observed time rate for yourself and my observed time rate for you are different as you move."
Where does the computer come into play? Maybe for deriving the Lorentz transformations, or calculating something else necessary to solidify the theory, but this as well as Schwartzchild's work coming up with solutions to the EFE, well, that's all computational physics, not theory.
Theory is the Gedankenexperiments behind the idea, not being a number crunching machine.
I also mentioned the fact, that a theorist will have an easier time if they have a good (relevant) computational program to work with while developing their theory, (or working with another's)