When I was flying I noticed that the engines were rotating really slowly. I could clearly see the swirl in the centre and it was slow. This is annoying
Anything to do with animations etc is because the aircraft hasnt had a rework in quite a while.
Its probably because of what @Mags885 has said though. 👇
So the speed of a turbine at full speed is too high for the human eye to break down into individual frame rate. Your brain cannot process it so slows down the rotation.
Basically the same effect as happens here:
The A330s simulate that very well, I love to switch to wing view while throttling up.