The supposed performance gains from monolithic kernel being wasted on features that mimic microkernel features.
So two things:
1. Containers don't have a meaningful performance hit. (They are semi-frequently used with things that can have a perf hit, like overlay filesystems, but this is generally easy to skip when it matters.)
2. I don't think containers meaningfully mimic microkernel features. If I run everything on my laptop in a container, and a device driver crashes, then the machine is still hosed.
2. It depends on what the containers are being used for. Microkernels aren't only about using drivers in userspace.
That is what happens when people don't update themselves.