They actually collaborated with ID Software to port Doom 2016's per object motion blur.
Reddit (and Lemmy) absolutely hate motion blur, but it's actually extremely important to create fluidity and it works super well.
The difference in that normally games just blur the entire frame, which can be distracting and look ugly. If you do it per object and actually handle the camera and parallax correctly, 30 FPS with motion blur can feel significantly smoother.
The game is also reasonably good at balancing CPU and GPU loads, so although you're running at low frame rates, you're probably getting a stabilized frame pacing.