Kernel Design microkernel vs. multikernel

Why was the choice of the kernel implementation fallen on the microkernel and not on a more modern design like a multikernel?

Does Multikernel mean a combination of monolithik kernal and microkernal?

I’m talking about a multikernel as used in the “Barrelfish OS”. It’s kind of an alternative Idea on how we deal with multicore systems.
For your Interest: http://www.barrelfish.org/publications/TN-000-Overview.pdf, Chapter 1.1 and 1.2

So why didn’t we use a Multikernel then?

Yeah, that’s exactly my question

So you might want to meet stratact from the chat forum he explained why multikernel is not a good approach.

https://chat.redox-os.org

I didn’t quite understand what he said its too techinical, but he did suggest what would be the best is to use a multi microkernel.