Cooperative scheduling would require provable upper limits on the number of instructions run by process between calls to a yield function. When the process is a compute task with an input of variable size, this would result in the need to count iterations and branch in inner loops that you want to be fast. I am not sold on the idea that such an overhead is lower in that case than interrupt driven preemptive scheduling.

Also, task prioritization can be a problem: the rate at which an interrupt-less cooperatively scheduled system must reschedule depends on the response time for the task with the shortest maximum response time. You must guarantee that the scheduler can switch to it in time to meet its deadline. This can increase the scheduling frequency for everything, requiring all components of the system to call the scheduler more often. So you'd have pretty tight coupling between everything.