Hey, I've been working on an RTS for about six months now and I'm not even close to finishing. I stopped because of school right now, but when I get started again, I still have nearly a hundred things to model, panels to construct, scripts to write and plans to either add or edit. Lets look at what I have done so far: First I planned it in a notebook. Then I did some of the models. Then I started some of the panels and some of the scripts. And it took me 6 months to do that.

So yeah, an RTS is possible. its just a lot of work and you need to know what you are doing. You have to be a competent scripter to make it work.

I use 3dgs, gameSpace, Photoshop, Ultimate Unwrap, MED and SED to put everything together. So it takes multiple programs as well.