The tech stagnation over thousand-year timescales isn't easy to reconcile with what we know how tech advances, especially over the last century or so. The tech in KOTOR and TOR is definitely chunkier and less refined than in the movie era, but its function is pretty much the same. Hyperdrive, blasters, lightsabers, etc.. Advances do take place, however. And keep in mind that over thousands of years there could still be analogues to the "Dark Ages" where knowledge was lost.