You're late to the party, as Dragonfly is already outdoing Linux in some areas, such as the network stack[0].
>But most BSD ( including OpenBSD which you just praised ) is monolith as well.
I praised them for the engineering they've been doing. They still retain flexibility, despite the monolithic design. Linux went all-in with their smp locking and kernel preemption, and the costs of getting any work done on the source code have skyrocketed since.
>Perhaps the future is hybrid, only time will tell.
Hybrid is a marketing term. It's a blurry line between a monolith and a so-called hybrid. What they're marketing is structure. Structure is good. Netbsd is an example of a well structured system. Linux is the counterpart: A poorly structured one.
>Monoliths have been great for general and corporate use.
UNIX is an old design. Corporate hates taking risks. However, there's massive scale deployments of microkernel systems, they're just not on your face; the visibility is actually quite low for these. But they do tasks that greatly benefit from or outright require such a design.
Monolithic design limits are more evident than ever, as we're hitting them left and right. So this is changing. For instance, besides systems such as Genode and HelenOS, Google is working on Fuchsia and Huawei on HarmonyOS. Brace for impact, as waves will be made when this all finally hits.