My memory could be playing tricks as I haven't been on ST since 1998, but it was a little scratchy in places last time I rode it. I think it's all digital now?

It's also possible the projection equipment was kept in better shape than most multiplexes, combined with the short length of both attractions might have helped?

As the projector for ST would have been "on board" the simulator, it must have been designed to cope with all the movement of the ride?

I suspect all the video monitors throughout the ride were fed by Laserdisc, especially the monitor aboard the starspeeder with the flight instructions, communications from rebel pilots, and the "rear" view of Artoo in his socket.