We have been unable to enable prioritization support at the execution control layer since we added this code several years ago due to performance changes, and we don't have a clear workload that demonstrates the value to customers of doing prioritization at the execution control layer.

We spent some time trying to resolve the performance issues by relaxing the strict queueing behavior, which helps in some workloads but hurts others, including some of the workloads we expected prioritization to show a benefit for. We also couldn't get a clear signal of user-benefit from enabling this feature as written (see SERVER-96049).

Let's remove it for now and revisit priority support in the ticketing system when the use-case is better understood and high value and we know where in the system we want to do it. In the meanwhile, it's complicating the code by keeping everything virtualized.