With the advent of multi core CPUs monolithic kernels jumping in on doing slow shared memory concurrency kind of killed the idea of monolithic kernels to be fas

With the advent of multi core CPUs monolithic kernels jumping in on doing slow shared memory concurrency kind of killed the idea of monolithic kernels to be fast. They can't be fast unless they do actor model, but it goes against the idea of monoliths, hence they can't do better than microkernels.