If 10% of your OS code is in a small piece that might be called a microkernel, and 90% is in one huge blob that implements everything else, then you don't really have a microkernel OS.
Or to phrase that more directly at the point: for monolithic kernels to be obsolete you have to break up the monolithic part, not just shim a microkernel hypervisor on top of it.
Tanenbaum was right, the future of the Linux kernel is dire, and it's been a huge setback to operating systems research in practical terms.
Fortunately, vendors are gradually moving away from Linux, having been hamstrung by its failures. Google is planning to move to a capability-based microkernel in the coming years for Android and ChromeOS, and Huawei has already done so with HarmonyOS.
In a hundred years, Linux will be a footnote in computing history.
